Publications

Ignacio Gutierrez Lezama, Nicolas Ubrig, Evgeniy Ponomarev and Alberto Morpurgo

Nature Reviews Physics (2021)

Reliable and precise measurements of the relative energy of band edges in 2D semiconductors are needed to determine band gaps and band offsets, as well as to establish the band diagram of devices and heterostructures. However, commonly employed techniques such as optical studies and scanning…

Daniil Domaretskiy, Nicolas Ubrig, Ignacio Gutierrez Lezama, Michaël Tran and Alberto Morpurgo

2D Materials 8 045016 (2021)

Christophe Berthod, Haijing Zhang, Alberto Morpurgo and Thierry Giamarchi

Physical Review Research 3 4, 043036 (2021)

Impressive progress in the control of atomically thin crystals is now enabling the realization of gated structures in which two electrodes are separated by atomic scale distances. The electrical capacitance of these structures is determined by phenomena that are not relevant in capacitors with…

Zhe Wang, Ignacio Gutierrez Lezama, Dumitru Dumcenco, Nicolas Ubrig, Takashi Taniguchi, Kenji Watanabe, Enrico Giannini, Marco Gibertini and Alberto Morpurgo

Nature communications 12 1, 6659 (2021)

Recent experiments on van der Waals antiferromagnets have shown that measuring the temperature ( T ) and magnetic field ( H ) dependence of the conductance allows their magnetic phase diagram to be mapped. Similarly, experiments on ferromagnetic CrBr ₃ barriers enabled the Curie…

Gen Long, Hugo Henck, Marco Gibertini, Dumitru Dumcenco, Zhe Wang, Takashi Taniguchi, Kenji Watanabe, Enrico Giannini and Alberto Morpurgo

Nano letters 20 4, 2452-2459 (2020)

Diego Mauro, Hugo Henck, Marco Gibertini, Michele Filippone, Enrico Giannini, Ignacio Gutierrez Lezama and Alberto Morpurgo

2D Materials 7 025042 (2020)

Monolayer jacutingaite (Pt2HgSe3) has been recently identified as a candidate quantum spin Hall system with a 0.5 eV band gap, but no transport measurements have been performed so far on this material, neither in monolayer nor in the bulk. By using a dedicated high-pressure technique, we grow…

Giulia Tenasini, Edoardo Martino, Nicolas Ubrig, Nirmal J. Ghimire, Helmuth Berger, Oksana Zaharko, Fengcheng Wu, J. F. Mitchell, Ivar Martin, László Forró and Alberto Morpurgo

Physical Review Research 2 2, 023051 (2020)

The discovery of the anomalous Hall effect (AHE) in bulk metallic antiferromagnets (AFMs) motivates the search of the same phenomenon in two-dimensional (2D) systems, where a quantized anomalous Hall conductance can, in principle, be observed. Here we present experiments on microfabricated devices…

Bojja Aditya Reddy, Evgeniy Ponomarev, Ignacio Gutierrez Lezama, Nicolas Ubrig, Céline Barreteau, Enrico Giannini and Alberto Morpurgo

Nano Letters 20 2, 1322-1328 (2020)

The assembly of suitably designed van der Waals (vdW) heterostructures represents a new approach to produce artificial systems with engineered electronic properties. Here, we apply this strategy to realize synthetic semimetals based on vdW interfaces formed by two different semiconductors. Guided…

Nicolas Ubrig, Zhe Wang, Jérémie Teyssier, Takashi Taniguchi, Kenji Watanabe, Enrico Giannini, Alberto Morpurgo and Marco Gibertini

2D Materials 7 1, 015007 (2020)

Chromium triiodide, CrI3, is emerging as a promising magnetic two-dimensional semiconductor where spins are ferromagnetically aligned within a single layer. Potential applications in spintronics arise from an antiferromagnetic ordering between adjacent layers that gives rise to spin filtering and a …

Nicolas Ubrig, Evgeniy Ponomarev, Johanna Zultak, Daniil Domaretskiy, Viktor Zólyomi, Daniel Terry, James Howarth, Ignacio Gutierrez Lezama, Alexander Zhukov, Zakhar R. Kudrynskyi, Zakhar D. Kovalyuk, Amalia Patané, Takashi Taniguchi, Kenji Watanabe, Roman V. Gorbachev, Vladimir I. Fal'ko and Alberto Morpurgo

Nature Materials (2020)

Van der Waals (vdW) materials offer new ways to assemble artificial electronic media with properties controlled at the design stage, by combining atomically defined layers into interfaces and heterostructures. Their potential for optoelectronics stems from the possibility to tailor the spectral…

A Delhomme, D Vaclavkova, A Slobodeniuk, M Orlita, M Potemski, D M Basko, K Watanabe, T Taniguchi, Diego Mauro, Céline Barreteau, Enrico Giannini, Alberto Morpurgo, Nicolas Ubrig and C Faugeras

2D Materials 7 041002 (2020)

Optical selection rules in monolayers of transition metal dichalcogenides and of their heterostructures are determined by the conservation of the z-component of the total angular momentum—J Z = L Z +S Z – associated with the C3 rotational lattice symmetry which assumes half integer values…

Marc Philippi

Thèse (2020)

In 2004, A. Geim and K. Novoselov realized the first isolation of a one-atom-thick material, graphene. The discovery of graphene, which was immediately followed by that of many other 2D materials with a large variety of physical properties, has paved the way to study physical properties in…

David Soler Delgado

Thèse (2020)

Graphene is a layer of carbon atoms arranged in a honeycomb lattice. In 2004, Andre Geim and Konstantin Novoselov made a revolutionary breakthrough as they were able to isolate graphene giving rise to a cascade of experiments that revealed its unique electronic properties. Electron interaction in…

Zhe Wang, Marco Gibertini, Dumitru Dumcenco, Takashi Taniguchi, Kenji Watanabe, Enrico Giannini and Alberto Morpurgo

Nature nanotechnology 14 12, 1116-1122 (2019)

Marco Gibertini, M. Koperski, Alberto Morpurgo and K. S. Novoselov

Nature nanotechnology 14 5, 408-419 (2019)

L. Thiel, Zhe Wang, M. A. Tschudin, D. Rohner, Ignacio Gutierrez Lezama, Nicolas Ubrig, Marco Gibertini, Enrico Giannini, Alberto Morpurgo and P. Maletinsky

Science 364 6444, 973-976 (2019)

The discovery of ferromagnetism in two-dimensional (2D) van der Waals (vdW) crystals has generated widespread interest. Making further progress in this area requires quantitative knowledge of the magnetic properties of vdW magnets at the nanoscale. We used scanning single-spin magnetometry based on …

Thibault Sohier, Evgeniy Ponomarev, Marco Gibertini, Helmuth Berger, Nicola Marzari, Nicolas Ubrig and Alberto Morpurgo

Physical Review X 9 3, 031019 (2019)

We report a combined experimental and theoretical investigation that reveals a new mechanism responsible for the enhancement of electron-phonon coupling in doped semiconductors in which multiple inequivalent valleys are simultaneously populated. Using Raman spectroscopy on ionic-liquid-gated…

Haijing Zhang, Christophe Berthod, Helmuth Berger, Thierry Giamarchi and Alberto Morpurgo

Nano Letters (2019)

Ionic liquid gated field-effect transistors (FETs) based on semiconducting transition metal dichalcogenides (TMDs) are used to study a rich variety of extremely interesting physical phenomena, but important aspects of how charge carriers are accumulated in these systems are not understood. We…

Evgeniy Ponomarev

Thèse (2019)

The isolation of single-atom-thick layer of graphite, very well known now as graphene, done by A.Geim and K.Novoselov (Nobel prize in physics 2010) in 2004 was a truly revolutionary breakthrough which opened up a new field of research and had a pronounced impact on multiple domains ranging from…

Young Woo Nam, Dongkeun Ki, David Soler Delgado and Alberto Morpurgo

Science 362 6412, 324-328 (2018)

Suspended Bernal-stacked graphene multilayers up to an unexpectedly large thickness exhibit a broken-symmetry ground state whose origin remains to be understood. We show that a finite-temperature second-order phase transition occurs in multilayers whose critical temperature (Tc) increases from 12…

Davide Costanzo, Haijing Zhang, Bojja Aditya Reddy, Helmuth Berger and Alberto Morpurgo

Nature nanotechnology 13 6, 483-488 (2018)

Zhe Wang, Deepak Sapkota, Takashi Taniguchi, Kenji Watanabe, David Mandrus and Alberto Morpurgo

Nano letters 18 7, 4303-4308 (2018)

Zhe Wang, Ignacio Gutierrez Lezama, Nicolas Ubrig, Martin Kroner, Marco Gibertini, Takashi Taniguchi, Kenji Watanabe, Ataç Imamoğlu, Enrico Giannini and Alberto Morpurgo

Nature Communications 9 2516 (2018)

Magnetic layered van der Waals crystals are an emerging class of materials giving access to new physical phenomena, as illustrated by the recent observation of 2D ferromagnetism in Cr2Ge2Te6 and CrI3. Of particular interest in semiconductors is the interplay between magnetism and transport, which…

Marc Philippi, Ignacio Gutierrez Lezama, Nicolas Ubrig and Alberto Morpurgo

Applied Physics Letters 113 3, 033502 (2018)

We explore solid electrolytes for electrostatic gating using field-effect transistors (FETs) in which thin WSe2 crystals are exfoliated and transferred onto a lithium-ion conducting glass ceramic substrate. For negative gate voltages (VG  0. For VG 

Evgeniy Ponomarev, Nicolas Ubrig, Ignacio Gutierrez Lezama, Helmuth Berger and Alberto Morpurgo

Nano Letters 18 8, 5146-5152 (2018)

Recent technical progress demonstrates the possibility of stacking together virtually any combination of atomically thin crystals of van der Waals bonded compounds to form new types of heterostructures and interfaces. As a result, there is the need to understand at a quantitative level how the…

Evgeniy Ponomarev, Arpad Pasztor, Adrien Waelchli, Alessandro Scarfato, Nicolas Ubrig, Christoph Renner and Alberto Morpurgo

ACS Nano (2018)

José Martinez Castro, Diego Mauro, Arpad Pasztor, Ignacio Gutierrez Lezama, Alessandro Scarfato, Alberto Morpurgo and Christoph Renner

Nano Letters 18 11, 6696-6702 (2018)

Many atomically thin exfoliated two-dimensional (2D) materials degrade when exposed to ambient conditions. They can be protected and investigated by means of transport and optical measurements if they are encapsulated between chemically inert single layers in the controlled atmosphere of a…

Irène Cucchi, Ignacio Gutierrez Lezama, Edoardo Cappelli, Siobhan Mckeown Walker, Flavio Yair Bruno, Giulia Tenasini, Lin Wang, Nicolas Ubrig, Céline Barreteau, Enrico Giannini, Marco Gibertini, Anna Tamai, Alberto Morpurgo and Felix Baumberger

Nano Letters (2018)

Two-dimensional crystals of semi-metallic van der Waals materials hold much potential for the realization of novel phases, as exemplified by the recent discoveries of a polar metal in few-layer 1T′-WTe2 and of a quantum spin Hall state in monolayers of the same material. Understanding these…

Davide Costanzo

Thèse (2018)

The existence of the first truly two-dimensional crystal was demonstrated experimentally in 2004 when Geim and Novoselov managed to isolate Graphene. The remarkable properties of this material triggered a surge of interest for 2D materials and, in recent years, the number of discovered 2D materials …

Young Woo Nam, Dongkeun Ki, David Soler Delgado and Alberto Morpurgo

Nature Physics 13 12, 1207-1214 (2017)

Ballistic transport occurs whenever electrons propagate without collisions deflecting their trajectory. It is normally observed in conductors with a negligible concentration of impurities, at low temperature, to avoid electron-phonon scattering. Here, we use suspended bilayer graphene devices to…

Lin Wang, N. Chepiga, Dongkeun Ki, L. Li, F. Li, W. Zhu, Y. Kato, O. S. Ovchinnikova, F. Mila, I. Martin, D. Mandrus and Alberto Morpurgo

Physical review letters 118 25, 257203 (2017)

Jun Yong Khoo, Alberto Morpurgo and Leonid Levitov

Nano letters 17 11, 7003-7008 (2017)

Nicolas Ubrig, Sanghyun Jo, Marc Philippi, Davide Costanzo, Helmuth Berger, Alexey Kuzmenko and Alberto Morpurgo

Nano letters 17 9, 5719-5725 (2017)

The band structure of many semiconducting monolayer transition metal dichalcogenides (TMDs) possesses two degenerate valleys, with equal and opposite Berry curvature. It has been predicted that, when illuminated with circularly polarized light, interband transitions generate an unbalanced…

Lin Wang, Ignacio Gutierrez Lezama, Céline Barreteau, Dongkeun Ki, Enrico Giannini and Alberto Morpurgo

Physical review letters 117 17, 176601 (2016)

Davide Costanzo, Sanghyun Jo, Helmuth Berger and Alberto Morpurgo

Nature nanotechnology 11 4, 339-344 (2016)

Yulia Krupskaya, Florian Rückerl, Martin Knupfer and Alberto Morpurgo

Advanced materials interfaces 3 10, 1500863 (2016)

Yulia Krupskaya, Ignacio Gutierrez Lezama and Alberto Morpurgo

Advanced functional materials 26 14, 2334-2340 (2016)

Beatrice Fraboni, Alessandro Fraleoni-Morgera, Yves Geerts, Alberto Morpurgo and Vitaly Podzorov

Advanced functional materials 26 14, 2229-2232 (2016)

Zhe Wang, Dongkeun Ki, Jun Yong Khoo, Diego Mauro, Helmuth Berger, Leonid S. Levitov and Alberto Morpurgo

Physical review. X 6 4, 041020 (2016)

Ignacio Gutierrez Lezama, Bojja Aditya Reddy, Nicolas Ubrig and Alberto Morpurgo

2D materials 3 4, 045016 (2016)

Young Woo Nam, Dongkeun Ki, Mikito Koshino, Edward McCann and Alberto Morpurgo

2D materials 3 4, 045014 (2016)

Lin Wang, Ignacio Gutierrez Lezama, Céline Barreteau, Nicolas Ubrig, Enrico Giannini and Alberto Morpurgo

Nature communications, 8892 (2015)

Either in bulk form, or in atomically thin crystals, layered transition metal dichalcogenides continuously reveal new phenomena. The latest example is 1T’-WTe2, a semimetal found to exhibit the largest known magnetoresistance in the bulk, and predicted to become a topological insulator in strained…

Evgeniy Ponomarev, Ignacio Gutierrez Lezama, Nicolas Ubrig and Alberto Morpurgo

Nano letters 15 12, 8289-8294 (2015)

We realize and investigate ionic liquid gated field-effect transistors (FETs) on large-area MoS2 monolayers grown by chemical vapor deposition (CVD). Under electron accumulation, the performance of these devices is comparable to that of FETs based on exfoliated flakes. FETs on CVD-grown material,…

Andrea C. Ferrari, Francesco Bonaccorso, Vladimir Fal'ko, Konstantin S. Novoselov, Stephan Roche, Peter Bøggild, Stefano Borini, Frank H. L. Koppens, Vincenzo Palermo, Nicola Pugno, José A. Garrido, Roman Sordan, Alberto Bianco, Laura Ballerini, Maurizio Prato, Elefterios Lidorikis, Jani Kivioja, Claudio Marinelli, Tapani Ryhänen, Alberto Morpurgo, Jonathan N. Coleman, Valeria Nicolosi, Luigi Colombo, Albert Fert, Mar Garcia-Hernandez, Adrian Bachtold, Grégory F. Schneider, Francisco Guinea, Cees Dekker, Matteo Barbone, Zhipei Sun, Costas Galiotis, Alexander N. Grigorenko, Gerasimos Konstantatos, Andras Kis, Mikhail Katsnelson, Lieven Vandersypen, Annick Loiseau, Vittorio Morandi, Daniel Neumaier, Emanuele Treossi, Vittorio Pellegrini, Marco Polini, Alessandro Tredicucci, Gareth M. Williams, Byung Hee Hong, Jong-Hyun Ahn, Jong Min Kim, Herbert Zirath, Bart J. van Wees, Herre van der Zant, Luigi Occhipinti, Andrea Di Matteo, Ian A. Kinloch, Thomas Seyller, Etienne Quesnel, Xinliang Feng, Ken Teo, Nalin Rupesinghe, Pertti Hakonen, Simon R. T. Neil, Quentin Tannock, Tomas Löfwander and Jari Kinaret

Nanoscale 7 11, 4598-4810 (2015)

Anna Grushina, Dongkeun Ki, Mikito Koshino, Aurelien A. L. Nicolet, Clément Faugeras, Edward McCann, Marek Potemski and Alberto Morpurgo

Nature communications 6 1, 6419 (2015)

Yulia Krupskaya, Marco Gibertini, Nicola Marzari and Alberto Morpurgo

Advanced materials 27 15, 2453-2458 (2015)

Zhe Wang, Dongkeun Ki, Hua Chen, Helmuth Berger, Allan H. MacDonald and Alberto Morpurgo

Nature communications 6 1, 8339 (2015)

Ignacio Gutierrez Lezama, Ashish Arora, Alberto Ubaldini, Céline Barreteau, Enrico Giannini, Marek Potemski and Alberto Morpurgo

Nano letters 15 4, 2336-2342 (2015)

Alberto Morpurgo

Nature physics 11 8, 625-626 (2015)

Sanghyun Jo, Davide Costanzo, Helmuth Berger and Alberto Morpurgo

Nano letters 15 2, 1197-1202 (2015)

Sandra Sopic

Thèse (2015)

The experimental results presented in this thesis show how the use of graphene provides new opportunities to investigate unexplored aspects of superconducting proximity effect (SPE). The interplay between decoherence and superconductivity is addressed by investigating the reentrance of SPE in…

Anna Grushina

Thèse (2015)

This Thesis presents experimental results of quantum transport measurements on high quality (HQ) suspended graphene devices. A high-precision transfer technique for graphene flakes was developed and used to fabricate a suspended HQ graphene device with additional bottom gate structure. The behavior …

Nuno Jose Guimaraes Couto, Davide Costanzo, Stephan Engels, Dongkeun Ki, Kenji Watanabe, Takashi Taniguchi, Christoph Stampfer, Francisco Guinea and Alberto Morpurgo

Physical review. X 4 4, 041019 (2014)

Ignacio Gutierrez Lezama, Alberto Ubaldini, Maria Longobardi, Enrico Giannini, Christoph Renner, Alexey Kuzmenko and Alberto Morpurgo

2D materials 1 2, 021002 (2014)

Semiconducting transition metal dichalcogenides (TMDs) have emerged as materials that can be used to realize two-dimensional (2D) crystals possessing rather unique transport and optical properties. Most research has so far focused on sulfur and selenium compounds, while tellurium-based materials…

Dongkeun Ki, Vladimir I. Fal'ko, Dmitry A. Abanin and Alberto Morpurgo

Nano letters, 140310104111005 (2014)

We investigate low-temperature magneto-transport in recently developed, high-quality multiterminal suspended bilayer graphene devices, enabling the independent measurement of the longitudinal and transverse resistance. We observe clear signatures of the fractional quantum Hall effect with different …

Fabio Deon, Sandra Sopic and Alberto Morpurgo

Physical review letters 112 12, 126803 (2014)

We discuss transport measurements through graphene Andreev interferometers exhibiting reentrance of the superconducting proximity effect. We observe that at high gate voltage (VBG) the energy dependence of the Andreev conductance oscillations exhibits a scaling in agreement with theoretical…

Sanghyun Jo, Nicolas Ubrig, Helmuth Berger, Alexey Kuzmenko and Alberto Morpurgo

Nano letters 14 4, 2019-2025 (2014)

We have realized ambipolar ionic liquid gated field-effect transistors based on WS2 mono- and bilayers, and investigated their opto-electronic response. A thorough characterization of the transport properties demonstrates the high quality of these devices for both electron and hole accumulation,…

Nicolas Ubrig, Sanghyun Jo, Helmuth Berger, Alberto Morpurgo and Alexey Kuzmenko

Applied physics letters 104 17, 171112 (2014)

We perform scanning photocurrent microscopy on WS2 ionic liquid-gated field effect transistors exhibiting high-quality ambipolar transport. By properly biasing the gate electrode, we can invert the sign of the photocurrent showing that the minority photocarriers are either electrons or holes. Both…

Nuno Jose Guimaraes Couto

Thèse (2014)

In this thesis we experimentally study charge transport through nano-devices made of graphene and topological insulators. In both these materials the low energy electronic states can be described by the Dirac equation. From systematic transport investigations of graphene devices on top of different …

Nikolas Aron Minder

Thèse (2014)

In this thesis we experimentally study the intrinsic charge transport properties in n-channel organic field-effect transistors and its disorder-induced suppression. We observe that certain molecular and crystal structures are beneficial for minimizing the disorder experienced by charge carriers and …

Christophe Caillier, Dongkeun Ki, Yuliya Lisunova, Iaroslav Gaponenko, Patrycja Paruch and Alberto Morpurgo

Nanotechnology 24 40, 405201 (2013)

To minimize parasitic doping effects caused by uncontrolled material adsorption, graphene is often investigated under vacuum. Here we report an entirely unexpected phenomenon occurring in vacuum systems, namely strong n-doping of graphene due to chemical species generated by common ion high-vacuum…

Dongkeun Ki and Alberto Morpurgo

Nano letters 13 11, 5165-5170 (2013)

We introduce a new scheme to realize suspended, multiterminal graphene structures that can be current annealed successfully to obtain uniform, very high quality devices. A key aspect is that the bulky metallic contacts are not connected directly to the part of graphene probed by transport…

Nikolas Aron Minder, Shaofeng Lu, Simone Fratini, Sergio Ciuchi, Antonio Facchetti and Alberto Morpurgo

Advanced materials 26 8, 1254-1260 (2013)

In organic field-effect transistors, the structure of the constituent molecules can be tailored to minimize the disorder experienced by charge carriers. Experiments on two perylene derivatives show that disorder can be suppressed by attaching longer core substituents – thereby reducing potential…

Ignacio Gutierrez Lezama and Alberto Morpurgo

MRS bulletin 38 01, 51-56 (2013)

Research on organic thin-film transistors tends to focus on improvements in device performance, but very little is understood about the ultimate limits of these devices, the microscopic physical mechanisms responsible for their limitations, and, more generally, the intrinsic transport properties of …

Anna Grushina, Dongkeun Ki and Alberto Morpurgo

Applied physics letters 102 22, 223102 (2013)

We have developed a process to fabricate suspended graphene devices with local bottom gates, and tested it by realizing electrostatically controlled pn junctions on a suspended graphene monolayer nearly 2 lm long. Measurements as a function of gate voltage, magnetic field, bias, and temperature…

Alberto Morpurgo

Nature physics 9 9, 532-533 (2013)

An electrically controllable spin–orbit interaction at the surface of transition-metal dichalcogenides highlights the wealth of unexpected physics that two-dimensional systems can offer.

Ignacio Gutierrez Lezama

Thèse (2013)

Dans cette thèse nous présentons les résultats expérimentaux obtenus à partir d’une série d’études systématiques, mesures sur des transistors à effet de champ, du transport électronique effectuées sur des cristaux moléculaires organiques. La discussion porte sur des propriétés…

Daniela Stornaiuolo, Stefano Gariglio, Nuno Jose Guimaraes Couto, Alexandre Fete, Andrea Caviglia, Gabriel Seyfarth, Didier Jaccard, Alberto Morpurgo and Jean-Marc Triscone

Applied physics letters 101 22, 222601 (2012)

Ignacio Gutierrez Lezama, Masaki Nakano, Nikolas Aron Minder, Zhihua Chen, Flavia Di Girolamo, Antonio Facchetti and Alberto Morpurgo

Nature materials 11 9, 788-794 (2012)

Organic semiconductors based on small conjugated molecules generally behave as insulators when undoped, but the heterointerfaces of two such materials can show electrical conductivity as large as in a metal. Although charge transfer is commonly invoked to explain the phenomenon, the details of the…

Ivar Martin and Alberto Morpurgo

Physical review. B, Condensed matter and materials physics 85 14 (2012)

In a variety of rare-earth-based compounds, singlet superconductivity coexists with helical magnetism. Here we demonstrate that surfaces of these systems should generically host a finite density of zero-energy Majorana modes. In the limit of vanishing disorder, these modes lead to a divergent…

M. Barra, F. V. Di Girolamo, Nikolas Aron Minder, Ignacio Gutierrez Lezama, Z. Chen, A. Facchetti, Alberto Morpurgo and A. Cassinese

Applied physics letters 100 13, 133301 (2012)

Bias stress effects in n-channel organic field-effect transistors(OFETs) are investigated using N,N′-bis(n-alkyl)-(1,7 and 1,6)-dicyanoperylene-3,4:9,10-bis(dicarboximide)s (PDIF-CN2) single-crystaldevices with Cytop gate dielectric, both under vacuum and in ambient. We find that the amount of…

Danièle Braga, Ignacio Gutierrez Lezama, Helmuth Berger and Alberto Morpurgo

Nano letters 12 10, 5218-5223 (2012)

We realized ambipolar field-effect transistors bycoupling exfoliated thin flakes of tungsten disulfide (WS2) with an ionic liquid dielectric. The devices show ideal electrical characteristics, including very steep subthreshold slopes for both electrons and holes and extremely low OFF-state…

Jian Li, Ivar Martin, Markus Buttiker and Alberto Morpurgo

Physica scripta T146, 014021 (2012)

The electronic structures of graphene systems and topological insulators have closely related features, such as a quantized Berry phase and zero-energy edge states. The reason for these similarities is that in both systems there are two relevant orbital bands, which generate the pseudo-spin degree…

Nikolas Aron Minder, Shimpei Ono, Zhihua Chen, Antonio Facchetti and Alberto Morpurgo

Advanced materials 24 4, 503-508 (2012)

The Hall effect and an increase of field-effect mobility with decreasing temperature is observed in n-channel single-crystal organic field-effect transistors (OFETs). A quantitative analysis of these findings, together with results on different p-channel transistors, indicate the importance of the…

Dongkeun Ki and Alberto Morpurgo

Physical review letters 108 26 (2012)

Suspended graphene nanoribbons formed during current annealing of suspended graphene flakes have been investigated experimentally. Transport measurements show the opening of a transport gap around charge neutrality due to the formation of ‘‘Coulomb islands”, coexisting with quantum Hall…

J. T. Ye, M. F. Craciun, M. Koshino, S. Russo, S. Inoue, H. T. Yuan, H. Shimotani, Alberto Morpurgo and Y. Iwasa

Proceedings of the National Academy of Sciences of the United States of America 108 32, 13002-13006 (2011)

We present a comparative study of high carrier density transport in mono-, bi-, and trilayer graphene using electric double-layer transistors to continuously tune the carrier density up to values exceeding 1014 cm-2. Whereas in monolayer the conductivity saturates, in bi- and trilayer filling of…

Nuno Jose Guimaraes Couto, Benjamin Sacepe and Alberto Morpurgo

Physical review letters 107 22 (2011)

We report transport measurements through graphene on SrTiO3 substrates as a function of magnetic field B, carrier density n, and temperature T. The large dielectric constant of SrTiO3 very effectively screens long-range electron-electron interactions and potential fluctuations, making Dirac…

Benjamin Sacepe, Jeroen Bart Oostinga, Jian Li, Alberto Ubaldini, Nuno Jose Guimaraes Couto, Enrico Giannini and Alberto Morpurgo

Nature communications 2, 575 (2011)

Three-dimensional topological insulators are characterized by the presence of a bandgap in their bulk and gapless Dirac fermions at their surfaces. New physical phenomena originating from the presence of the Dirac fermions are predicted to occur, and to be experimentally accessible via transport…

Jian Li, Ivar Martin, Markus Buttiker and Alberto Morpurgo

Nature physics 7 1, 38-42 (2011)

The edges of graphene-based systems possess unusual electronic properties, originating from the non-trivial topological structure associated with the pseudospinorial character of the electron wavefunctions. These properties, which have no analogue for electrons described by the Schrödinger…

Raoul Scherwitzl, Pavlo Zubko, Ignacio Gutierrez Lezama, Shimpei Ono, Alberto Morpurgo, Gustau Catalan and Jean-Marc Triscone

Advanced materials 22 48, 5517-5520 (2010)

Andrea Caviglia, Stefano Gariglio, Claudia Cancellieri, Benjamin Sacepe, Alexandre Fete, Nicolas Reyren, M. Gabay, Alberto Morpurgo and Jean-Marc Triscone

Physical review letters 105 23, 236802 (2010)

We report on a study of magnetotransport in LaAlO₃/SrTiO₃ interfaces characterized by mobilities of the order of several thousands cm2/V s. We observe Shubnikov–de Haas oscillations whose period depends only on the perpendicular component of the magnetic field. This…

Jian Li, Alberto Morpurgo, Markus Buttiker and Ivar Martin

Physical review. B, Condensed matter and materials physics 82 24 (2010)

We study the correspondence between the nontrivial topological properties associated with the individual valleys of gapped bilayer graphene (BLG), as a prototypical multivalley system, and the gapless modes at its edges and other interfaces. We find that the exact connection between the…

W.J.M. Naber, M.F. Craciun, J.H.J. Lemmens, A.H. Arkenbout, T.T.M. Palstra, Alberto Morpurgo and W.G. van der Wiel

Organic electronics 11 5, 743-747 (2010)

We report on single-crystal rubrene field-effect transistors (FETs) with ferromagnetic Co electrodes, tunnel-coupled to the conduction channel via an Al2O3 tunnel barrier. Magnetic and electronic characterization shows that the Al2O3 film not only protects the Co from undesired oxidation, but also…

Alberto Morpurgo and Björn Trauzettel

Semiconductor science and technology 25 3, 030301 (2010)

Editorial

S. Russo, M.F. Craciun, M. Yamamoto, Alberto Morpurgo and S. Tarucha

Physica. E, Low-dimensional systems and nanostructures 42 4, 677-679 (2010)

We report a systematic study of the total contact resistance present at the interface between a metal (Ti) and graphene layers of different, known thickness. By comparing devices fabricated on many different graphene flakes we demonstrate that the contact resistance consists of a gate independent…

Iddo Heller, Sohail Chatoor, Jaan Männik, Marcel A. G. Zevenbergen, Jeroen Bart Oostinga, Alberto Morpurgo, Cees Dekker and Serge G. Lemay

Nano letters 10 5, 1563-1567 (2010)

We report an experimental study of 1/f noise in liquid-gated graphene transistors. We show that the gate dependence of the noise is well described by a charge-noise model, whereas Hooge’s empirical relation fails to describe the data. At low carrier density, the noise can be attributed to…

Shimpei Ono, Nikolas Aron Minder, Z. Chen, A. Facchetti and Alberto Morpurgo

Applied physics letters 97 14, 143307 (2010)

High-performance n-type organic field-effect transistors were developed with ionic-liquid gates and N,N′′-bis(n-alkyl)-(1,7 and 1,6)-dicyanoperylene-3,4:9,10-bis(dicarboximide)s single-crystals. Transport measurements show that these devices reproducibly operate in ambient atmosphere with…

R. Danneau, F. Wu, M. Y. Tomi, Jeroen Bart Oostinga, Alberto Morpurgo and P. J. Hakonen

Physical review. B, Condensed matter and materials physics 82 16 (2010)

We have investigated shot noise and conduction of graphene field-effect nanoribbon devices at low temperature. By analyzing the exponential I-V characteristics of our devices in the transport gap region, we found out that transport follows variable range hopping laws at intermediate bias voltages 1

Masaki Nakano, H. Alves, A. S. Molinari, Shimpei Ono, Nikolas Aron Minder and Alberto Morpurgo

Applied physics letters 96 23, 232102 (2010)

We investigated transport properties of organic heterointerfaces formed by single-crystals of two organic donor-acceptor molecules, tetramethyltetraselenafulvalene and 7,7,8,8-tetracyanoquinodimethane (TCNQ). Whereas the individual crystals have unmeasurably high resistance, the interface exhibits…

Jeroen Bart Oostinga, Benjamin Sacepe, Monica F. Craciun and Alberto Morpurgo

Physical review. B, Condensed matter and materials physics 81 19 (2010)

We investigate magnetotransport through graphene nanoribbons as a function of gate and bias voltage, and temperature. We find that a magnetic field systematically leads to an increase in the conductance on a scale of a few tesla. This phenomenon is accompanied by a decrease in the energy scales…

Toshihiko Kaji, Taishi Takenobu, Alberto Morpurgo and Yoshihiro Iwasa

Advanced materials 21 36, 3689-3693 (2009)

R. Danneau, F. Wu, M.F. Craciun, S. Russo, M.Y. Tomi, J. Salmilehto, Alberto Morpurgo and P.J. Hakonen

Solid state communications 149 27-28, 1050-1055 (2009)

We have investigated shot noise at microwave frequencies in wide-aspect-ratio graphene sheets in the temperature range of 4.2_30 K. We find that for our short .L < 300 nm/ graphene samples with width over length ratio W=L > 3, the Fano factor F reaches a maximum F _ 1=3 at the Dirac point and that…

M. F. Craciun, S. Russo, M. Yamamoto, Jeroen Bart Oostinga, Alberto Morpurgo and S. Tarucha

Nature nanotechnology 4 6, 383-388 (2009)

Graphene-based materials are promising candidates for nanoelectronic devices because very high carrier mobilities can be achieved without the use of sophisticated material preparation techniques1. However, the carrier mobilities reported for single-layer and bilayer graphene are still less than…

S. Russo, M. F. Craciun, M. Yamamoto, S. Tarucha and Alberto Morpurgo

New journal of physics 11 9, 095018 (2009)

We discuss transport through double-gated single- and few-layer graphene devices. This kind of device configuration has been used to investigate the modulation of the energy band structure through the application of an external perpendicular electric field, a unique property of few-layer graphene…

Ignacio Gutierrez Lezama and Alberto Morpurgo

Physical review letters 103 6 (2009)

We investigate rubrene single-crystal field-effect transistors, whose stability and reproducibility are sufficient to measure systematically the shift in threshold voltage as a function of channel length and source-drain voltage. The shift is due to space charge transferred from the contacts and…

Anna S. Molinari, Helena Alves, Zhihua Chen, Antonio Facchetti and Alberto Morpurgo

Journal of the American Chemical Society 131 7, 2462-2463 (2009)

Single-crystal field-effect transistors (FETs) based on a fluorocarbon-substituted dicyanoperylene-3,4:9,10-bis(dicarboximide) [PDIF-CN2] were fabricated by lamination of the semiconductor crystal on Si-SiO2/PMMA-Au gate-dielectric-contact substrates. These devices were characterized both in vacuum …

Monica F. Craciun, Gianluca Giovannetti, Sven Rogge, Geert Brocks, Alberto Morpurgo and Jeroen van den Brink

Physical review. B, Condensed matter and materials physics 79 12 (2009)

We investigate electronic transport through pentacene thin films intercalated with potassium. From temperature-dependent conductivity measurements we find that potassium-intercalated pentacene shows metallic behavior in a broad range of potassium concentrations. Surprisingly, the conductivity…

Xinglan Liu, Jeroen Bart Oostinga, Alberto Morpurgo and Lieven M. K. Vandersypen

Physical review. B, Condensed matter and materials physics 80 12 (2009)

Coulomb blockade is observed in a graphene nanoribbon device with a top gate. When two pn junctions are formed via the back gate and the local top gate, electrons are confined between the pn junctions which act as the barriers. When no pn junctions are induced by the gate voltages, electrons are…

Alberto Morpurgo

Nature 462 7270, 170-171 (2009)

Graphene continues to surprise physicists with its remarkable electronic properties. Experiments now show that electrons in the material can team up to behave as if they are only fragments of themselves.

Hangxing Xie, H. Alves and Alberto Morpurgo

Physical review. B, Condensed matter and materials physics 80 24 (2009)

We perform a combined experimental and theoretical study of tetramethyltetraselenafulvalene (TMTSF) single-crystal field-effect transistors, whose electrical characteristics exhibit clear signatures of the intrinsic transport properties of the material. We present a simple, well-defined model based …

S. Fratini, Alberto Morpurgo and S. Ciuchi

Journal of physics and chemistry of solids 69 9, 2195-2198 (2008)

R. Danneau, F. Wu, M. F. Craciun, S. Russo, M. Y. Tomi, J. Salmilehto, Alberto Morpurgo and P. J. Hakonen

Physical review letters 100 19, 196802 (2008)

A. S. Molinari, I. Gutiérrez Lezama, P. Parisse, T. Takenobu, Y. Iwasa and Alberto Morpurgo

Applied physics letters 92 13, 133303 (2008)

Helena Alves, Anna S. Molinari, Hangxing Xie and Alberto Morpurgo

Nature materials 7 7, 574-580 (2008)

S Fratini, H Xie, I N Hulea, S Ciuchi and Alberto Morpurgo

New journal of physics 10 3, 033031 (2008)

Saverio Russo, Jeroen B. Oostinga, Dominique Wehenkel, Hubert B. Heersche, Samira Shams Sobhani, Lieven M. K. Vandersypen and Alberto Morpurgo

Physical review. B, Condensed matter and materials physics 77 8, 085413 (2008)

S. Fratini, Alberto Morpurgo and S. Ciuchi

Physica status solidi. C, Current topics in solid state physics 5 3, 718-721 (2008)

Ivar Martin, Ya. M. Blanter and Alberto Morpurgo

Physical review letters 100 3, 036804 (2008)

R. Danneau, F. Wu, M. F. Craciun, S. Russo, M. Y. Tomi, J. Salmilehto, Alberto Morpurgo and P. J. Hakonen

Journal of low temperature physics 153 5-6, 374-392 (2008)

We have investigated electrical transport and shot noise in graphene field effect devices. In large width over length ratio W/L graphene strips, we have measured shot noise at low frequency (f=600–850 MHz) in the temperature range of 4.2–30 K. We observe a minimum conductivity of 4e2πh and a…

Anna Molinari, Ignacio Gutierrez Lezama, Iulian N. Hulea, Saverio Russo and Alberto Morpurgo

Applied physics letters 90 21, 212103 (2007)

Jeroen B. Oostinga, Hubert B. Heersche, Xinglan Liu, Alberto Morpurgo and Lieven M. K. Vandersypen

Nature materials 7 2, 151-157 (2007)

Hubert B. Heersche, Pablo Jarillo-Herrero, Jeroen B. Oostinga, Lieven M. K. Vandersypen and Alberto Morpurgo

Nature 446 7131, 56-59 (2007)

B. Trauzettel, Ya. M. Blanter and Alberto Morpurgo

Physical review. B, Condensed matter and materials physics 75 3, 035305 (2007)

P. Recher, B. Trauzettel, A. Rycerz, Ya. M. Blanter, C. W. J. Beenakker and Alberto Morpurgo

Physical review. B, Condensed matter and materials physics 76 23, 235404 (2007)

S. Russo, J. Tobiska, T. M. Klapwijk and Alberto Morpurgo

Physical review letters 99 8, 086601 (2007)

Hubert B. Heersche, Pablo Jarillo-Herrero, Jeroen B. Oostinga, Lieven M.K. Vandersypen and Alberto Morpurgo

Solid state communications 143 1-2, 72-76 (2007)

H. B. Heersche, P. Jarillo-Herrero, J. B. Oostinga, L. M.K. Vandersypen and Alberto Morpurgo

The European physical journal. Special topics 148 1, 27-37 (2007)

Jeroen van den Brink and Alberto Morpurgo

Nature 450 7167, 177-178 (2007)

Alberto Morpurgo and F. Guinea

Physical review letters 97 19, 196804 (2006)

I. N. Hulea, S. Fratini, H. Xie, C. L. Mulder, N. N. Iossad, G. Rastelli, S. Ciuchi and Alberto Morpurgo

Nature materials 5 12, 982-986 (2006)

Serena Margadonna, Kosmas Prassides, Yoshihiro Iwasa, Yasujiro Taguchi, Monica F. Craciun, Sven Rogge and Alberto Morpurgo

Inorganic chemistry 45 26, 10472-10478 (2006)

S. Russo, S.T.B. Goennenwein, Alberto Morpurgo, T.M. Klapwijk, T.M. van Roy and J. De Boeck

AIP conference proceedings 850, 1275 (2006)

M.E. Gershenson, V. Podzorov and Alberto Morpurgo

Reviews of modern physics 78 3, 973-989 (2006)

Small-molecule organic semiconductors, together with polymers, form the basis for the emerging field of organic electronics. Despite the rapid technological progress in this area, our understanding of fundamental electronic properties of these materials remains limited. Recently developed organic…

A Cottet, T Kontos, S Sahoo, H T Man, M-S Choi, W Belzig, C Bruder, Alberto Morpurgo and C Schönenberger

Semiconductor science and technology 21 11, S78-S95 (2006)

S. Russo, M. Kroug, T.M. Klapwijk and Alberto Morpurgo

AIP conference proceedings 850, 877-878 (2006)

H. T. Man, I. J. W. Wever and Alberto Morpurgo

Physical review. B, Condensed matter and materials physics 73 24, 241401 (2006)

M. F. Craciun, S. Rogge, M.-J. L. den Boer, S. Margadonna, K. Prassides, Y. Iwasa and Alberto Morpurgo

Advanced materials 18 3, 320-324 (2006)

Iulian N. Hulea, Saverio Russo, Anna Molinari and Alberto Morpurgo

Applied physics letters 88 11, 113512 (2006)

C. H. Ahn, A. Bhattacharya, M. Di Ventra, J. N. Eckstein, C. Daniel Frisbie, M. E. Gershenson, A. M. Goldman, I. H. Inoue, J. Mannhart, Andrew J. Millis, Alberto Morpurgo, Douglas Natelson and Jean-Marc Triscone

Reviews of modern physics 78 4, 1185-1212 (2006)

Application of the field-effect transistor principle to novel materials to achieve electrostatic doping is a relatively new research area. It may provide the opportunity to bring about modifications of the electronic and magnetic properties of materials through controlled and reversible changes of…

R. W. I. de Boer, N. N. Iosad, A. F. Stassen, T. M. Klapwijk and Alberto Morpurgo

Applied physics letters 86 3, 032103 (2005)

Monica F. Craciun, Sven Rogge and Alberto Morpurgo

Journal of the American Chemical Society 127 35, 12210-12211 (2005)

R. W. I. de Boer and Alberto Morpurgo

Physical review. B, Condensed matter and materials physics 72 7, 073207 (2005)

H. T. Man and Alberto Morpurgo

Physical review letters 95 2, 026801 (2005)

S. Russo, M. Kroug, T. M. Klapwijk and Alberto Morpurgo

Physical review letters 95 2, 027002 (2005)

S. T. B. Goennenwein, S. Russo, Alberto Morpurgo, T. M. Klapwijk, W. Van Roy and J. De Boeck

Physical review. B, Condensed matter and materials physics 71 19, 193306 (2005)

F. E. Meijer, Alberto Morpurgo, T. M. Klapwijk and J. Nitta

Physical review letters 94 18, 186805 (2005)

R. W. I. de Boer, A. F. Stassen, M. F. Craciun, C. L. Mulder, A. Molinari, S. Rogge and Alberto Morpurgo

Applied physics letters 86 26, 262109 (2005)

Jeroen van den Brink, Geert Brocks and Alberto Morpurgo

Journal of magnetism and magnetic materials 290-291, 294-297 (2005)

R. W. I. de Boer, M. Jochemsen, T. M. Klapwijk, Alberto Morpurgo, J. Niemax, A. K. Tripathi and J. Pflaum

Journal of applied physics 95 3, 1196-1202 (2004)

F. E. Meijer, Alberto Morpurgo, T. M. Klapwijk, T. Koga and J. Nitta

Physical review. B, Condensed matter and materials physics 69 3, 035308 (2004)

F.E. Meijer, J. Nitta, T. Koga, Alberto Morpurgo and T.M. Klapwijk

Physica. E, Low-dimensional systems and nanostructures 22 1-3, 402-405 (2004)

N. N. Iosad, G. J. Ruis, E. V. Morks, Alberto Morpurgo, N. M. van der Pers, P. F. A. Alkemade and V. G. M. Sivel

Journal of applied physics 95 12, 8087-8091 (2004)

R. W. I. de Boer, M. E. Gershenson, Alberto Morpurgo and V. Podzorov

Physica status solidi. A, Applied research 201 6, 1302-1331 (2004)

Geert Brocks, Jeroen van den Brink and Alberto Morpurgo

Physical review letters 93 14, 146405 (2004)

A. F. Stassen, R. W. I. de Boer, N. N. Iosad and Alberto Morpurgo

Applied physics letters 85 17, 3899-3901 (2004)

F. Meijer, Alberto Morpurgo, T. Klapwijk, T. Koga and J. Nitta

Physical review. B, Condensed matter and materials physics 70 20, 201307 (2004)

D.B.A. Rep, Alberto Morpurgo, W. G. Sloof and T. M. Klapwijk

Journal of applied physics 93 4, 2082-2090 (2003)

M. F. Craciun, S. Rogge, D. A. Wismeijer, M. J. L. den Boer, T. M. Klapwijk and Alberto Morpurgo

AIP conference proceedings 696 1 (2003)

R. W. I. de Boer, T. M. Klapwijk and Alberto Morpurgo

Applied physics letters 83 21, 4345-4347 (2003)

D.B.A. Rep, Alberto Morpurgo and T.M. Klapwijk

Organic electronics 4 4, 201-207 (2003)

M. D. Upward, L. P. Kouwenhoven, Alberto Morpurgo, N. Kikugawa, Z. Q. Mao and Y. Maeno

Physical review. B, Condensed matter 65 22, 220512 (2002)

Y. V. Kervennic, H. S. J. Van der Zant, Alberto Morpurgo, L. Gurevich and L. P. Kouwenhoven

Applied physics letters 80 2, 321-323 (2002)

F. E. Meijer, Alberto Morpurgo and T. M. Klapwijk

Physical review. B, Condensed matter 66 3, 033107 (2002)

M.D. Upward, J.W. Janssen, L. Gurevich, Alberto Morpurgo and L.P. Kouwenhoven

Applied physics. A, Materials science & processing 72 S2, S253-S256 (2001)

Alberto Morpurgo, J. J. A. Baselmans, B. J. van Wees and T. M. Klapwijk

Journal of low temperature physics 118 5-6, 637-651 (2000)

Linda G. M. Olofsson, S. H. Magnus Persson, Alberto Morpurgo, Charles M. Marcus, Dimitri Golubev, Linda K. Gunnarsson and Yirmin Yao

Journal of low temperature physics 118, 343-353 (2000)

Alberto Morpurgo, J Kong, C.M Marcus and H Dai

Physica. B, Condensed matter 280 1-4, 382-383 (2000)

J.J.A. Baselmans, Alberto Morpurgo, B.J. van Wees and T.M. Klapwijk

Superlattices and microstructures 25 5-6, 973-982 (1999)

Alberto Morpurgo, J. Kong, C. M. Marcus and H. Dai

Science 286 5438, 263-265 (1999)

J. Kong, C. Zhou, Alberto Morpurgo, H.T. Soh, C.F. Quate, C. Marcus and H. Dai

Applied physics. A, Materials science & processing 69 3, 305-308 (1999)

Alberto Morpurgo, C. M. Marcus and D. B. Robinson

Applied physics letters 74 14, 2084-2086 (1999)

Hyongsok T. Soh, Calvin F. Quate, Alberto Morpurgo, Charles M. Marcus, Jing Kong and Hongjie Dai

Applied physics letters 75 5, 627-629 (1999)

J. J. A. Baselmans, Alberto Morpurgo, B. J. van Wees and T. M. Klapwijk

Nature 397 6714, 43-45 (1999)

Alberto Morpurgo, J. P. Heida, T. M. Klapwijk, B. J. van Wees and G. Borghs

Physical review letters 83 8, 1701 (1999)

Alberto Morpurgo, J.P Heida, B.J van Wees, T.M Klapwijk and G Borghs

Solid-state electronics 42 7-8, 1099-1102 (1998)

Alberto Morpurgo, B.J van Wees, T.M Klapwijk and G Borghs

Physica. B, Condensed matter 249-251, 458-461 (1998)

Alberto Morpurgo, J.P Heida, B.J van Wees, T.M Klapwijk and G Borghs

Physica. B, Condensed matter 249-251, 509-512 (1998)

Alberto Morpurgo, J. P. Heida, T. M. Klapwijk, B. J. van Wees and G. Borghs

Physical review letters 80 5, 1050-1053 (1998)

Alberto Morpurgo, T. M. Klapwijk and B. J. van Wees

Applied physics letters 72 8, 966-968 (1998)

Alberto Morpurgo, B. J. van Wees, T. M. Klapwijk and G. Borghs

Physical review letters 79 20, 4010-4013 (1997)

Alberto Morpurgo, B. J. van Wees, T. M. Klapwijk and G. Borghs

Applied physics letters 70 11, 1435-1437 (1997)

Alberto Morpurgo, S. Holl, B. J. van Wees, T. M. Klapwijk and G. Borghs

Physical review letters 78 13, 2636-2639 (1997)

B. J. van Wees, S. G. den Hartog and Alberto Morpurgo

Physical review letters 76 8, 1402 (1996)

Alberto Morpurgo and Fabio Beltram

Physical review. B, Condensed matter 50 2, 1325-1328 (1994)