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Janssen, M.F.W.H.A. (author), Van der Duin, P. (author), Wagenaar, R.W. (author), Bicking, M. (author), Wimmer, M.A. (author), Dawes, S. (author), Petrauskas, R. (author)E-government research is currently at a stage of consolidation and new orientation. Smaller steps of government modernization have in part been successfully implemented; larger ones still lie ahead of us. Within an EC funded project, a roadmap for egovernment is being defined. Thereby, scenario building about the future is being used to grasp...conference paper 2007
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Wimmer, M. (author), Codagnone, C. (author), Janssen, M.F.W.H.A. (author)E-government research has become a recognized research domain and many policies and strategies are formulated for e-government implementations. Most of these target the next few years and limited attention has been giving to the long term. The eGovRTD2020, a European Commission co-funded project, investigated the future research on e-government...conference paper 2008
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Pikulin, D.I. (author), Hyart, T. (author), Mi, S. (author), Tworzydlo, J. (author), Wimmer, M.T. (author), Beenakker, C.W.J. (author)We calculate the conductance of a two-dimensional bilayer with inverted electron-hole bands to study the sensitivity of the quantum spin Hall insulator (with helical edge conduction) to the combination of electrostatic disorder and a perpendicular magnetic field. The characteristic breakdown field for helical edge conduction splits into two...journal article 2014
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Diez, M. (author), Dahlhaus, J.P. (author), Wimmer, M.T. (author), Beenakker, C.W.J. (author)The fractal spectrum of magnetic minibands (Hofstadter butterfly), induced by the moiré superlattice of graphene on a hexagonal crystal substrate, is known to exhibit gapped Dirac cones. We show that the gap can be closed by slightly misaligning the substrate, producing a hierarchy of conical singularities (Dirac points) in the band structure at...journal article 2014
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Van Weperen, I. (author), Tarasinski, B. (author), Eeltink, D. (author), Pribiag, V.S. (author), Plissard, S.R. (author), Bakkers, E.P.A.M. (author), Kouwenhoven, L.P. (author), Wimmer, M.T. (author)We use magnetoconductance measurements in dual-gated InSb nanowire devices, together with a theoretical analysis of weak antilocalization, to accurately extract spin-orbit strength. In particular, we show that magnetoconductance in our three-dimensional wires is very different compared to wires in two-dimensional electron gases. We obtain a...journal article 2015
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Qu, F. (author), Beukman, A.J.A. (author), Nadj-Perge, S. (author), Wimmer, M.T. (author), Nguyen, B.M. (author), Yi, W. (author), Thorp, J. (author), Sokolich, M. (author), Kiselev, A.A. (author), Manfra, M.J. (author), Marcus, C.M. (author), Kouwenhoven, L.P. (author)Among the theoretically predicted two-dimensional topological insulators, InAs/GaSb double quantum wells (DQWs) have a unique double-layered structure with electron and hole gases separated in two layers, which enables tuning of the band alignment via electric and magnetic fields. However, the rich trivial-topological phase diagram has yet to be...journal article 2015
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Tambouris, E. (author), Scholl, H.J. (author), Janssen, M.F.W.H.A. (author), Wimmer, M.A. (author), Tarabanis, K. (author), Gascó, M. (author), Klievink, A.J. (author), Lindgren, I. (author), Milano, M. (author), Panagiotopoulos, P. (author), Pardo, T.A. (author), Parycek, P. (author), Sæbø, O. (author)Electronic government and electronic participation continue to transform the public sector and society worldwide and are constantly being transformed themselves by emerging information and communication technologies. This book presents papers from the 14th International Federation for Information Processing’s EGOV conference (IFIP EGOV 2015),...book 2015
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Vuik, A. (author), Eeltink, D. (author), Akhmerov, A.R. (author), Wimmer, M.T. (author)One of the promising platforms for creating Majorana bound states is a hybrid nanostructure consisting of a semiconducting nanowire covered by a superconductor.Weanalyze the previously disregarded role of electrostatic interaction in these devices. Our main result is that Coulomb interaction causes the chemical potential to respond to an applied...journal article 2016
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Kjaergaard, M. (author), Nichele, F. (author), Suominen, H. J. (author), Nowak, M.P. (author), Wimmer, M (author), Akhmerov, A.R. (author), Folk, JA (author), Flensberg, K. (author), Shabani, J. (author), Palmstrøm, C. J. (author), Marcus, C. M. (author)Coupling a two-dimensional (2D) semiconductor heterostructure to a superconductor opens new research and technology opportunities, including fundamental problems in mesoscopic superconductivity, scalable superconducting electronics, and new topological states of matter. One route towards topological matter is by coupling a 2D electron gas...journal article 2016
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Zhang, H. (author), Gül, Önder (author), Conesa Boj, S. (author), Nowak, M.P. (author), Wimmer, M.T. (author), Zuo, K. (author), Mourik, Vincent (author), de Vries, F.K. (author), van Veen, J. (author), de Moor, M.W.A. (author), Bommer, J.D.S. (author), van Woerkom, D.J. (author), Car, Diana (author), Plissard, S.R. (author), Bakkers, E.P.A.M. (author), Quintero Perez, M. (author), Cassidy, M.C. (author), Koelling, Sebastian (author), Goswami, S. (author), Watanabe, Kenji (author), Taniguchi, Takashi (author), Kouwenhoven, Leo P. (author)Semiconductor nanowires have opened new research avenues in quantum transport owing to their confined geometry and electrostatic tunability. They have offered an exceptional testbed for superconductivity, leading to the realization of hybrid systems combining the macroscopic quantum properties of superconductors with the possibility to...journal article 2017
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Pekerten, B. (author), Teker, A. (author), Bozat, Ö. (author), Wimmer, M.T. (author), Adagideli, I (author)In this work, we investigate the effect of disorder on the topological properties of multichannel superconductor nanowires. While the standard expectation is that the spectral gap is closed and opened at transitions that change the topological index of the wire, we show that the closing and opening of a transport gap can also cause...journal article 2017
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Winkler, Georg W. (author), Varjas, D. (author), Skolasinski, R.J. (author), Soluyanov, Alexey A. (author), Troyer, Matthias (author), Wimmer, M.T. (author)Recent experiments on Majorana fermions in semiconductor nanowires [S. M. Albrecht, A. P. Higginbotham, M. Madsen, F. Kuemmeth, T. S. Jespersen, J. Nygård, P. Krogstrup, and C. M. Marcus, Nature (London) 531, 206 (2016)NATUAS0028-083610.1038/nature17162] revealed a surprisingly large electronic Landé g factor, several times larger than the...journal article 2017
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Beukman, A.J.A. (author), de Vries, F.K. (author), van Veen, J. (author), Skolasinski, R.J. (author), Wimmer, M.T. (author), Qu, F. (author), De Vries, David T. (author), Nguyen, Binh Minh (author), Kouwenhoven, Leo P. (author)The spin-orbit interaction is investigated in a dual gated InAs/GaSb quantum well. Using an electric field, the quantum well can be tuned between a single-carrier regime with exclusively electrons as carriers and a two-carrier regime where electrons and holes coexist. The spin-orbit interaction in both regimes manifests itself as a beating in...journal article 2017
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Nichele, Fabrizio (author), Kjaergaard, Morten (author), Suominen, Henri J. (author), Skolasinski, R.J. (author), Wimmer, M (author), Nguyen, Binh Minh (author), Qu, F. (author), Beukman, A.J.A. (author), Kouwenhoven, Leo P. (author)Transport measurements in inverted InAs/GaSb quantum wells reveal a giant spin-orbit splitting of the energy bands close to the hybridization gap. The splitting results from the interplay of electron-hole mixing and spin-orbit coupling, and can exceed the hybridization gap. We experimentally investigate the band splitting as a function of top...journal article 2017
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Kammhuber, J. (author), Cassidy, M.C. (author), Pei, F. (author), Nowak, M.P. (author), Vuik, A. (author), Gül, Önder (author), Car, D. (author), Plissard, S.R. (author), Bakkers, E.P.A.M. (author), Wimmer, M.T. (author), Kouwenhoven, Leo P. (author)The motion of an electron and its spin are generally not coupled. However in a one-dimensional material with strong spin-orbit interaction (SOI) a helical state may emerge at finite magnetic fields, where electrons of opposite spin will have opposite momentum. The existence of this helical state has applications for spin filtering and cooper...journal article 2017
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Meyer, S (author), Chen, Y. (author), Wimmer, S. (author), Althammer, M (author), Wimmer, T. (author), Schlitz, Richard (author), Geprags, S (author), Huebl, H (author), Kodderitzsch, D. (author), Ebert, H. (author), Bauer, G.E. (author), Gross, R (author), Goennenwein, S. T.B. (author)The observation of the spin Hall effect triggered intense research on pure spin current transport. With the spin Hall effect, the spin Seebeck effect and the spin Peltier effect already observed, our picture of pure spin current transport is almost complete. The only missing piece is the spin Nernst (-Ettingshausen) effect, which so far has...journal article 2017
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Istas, Mathieu (author), Groth, Christoph (author), Akhmerov, A.R. (author), Wimmer, M.T. (author), Waintal, Xavier (author)We propose a robust and efficient algorithm for computing bound states of infinite tight-binding systems that are made up of a finite scattering region connected to semi-infinite leads. Our method uses wave matching in close analogy to the approaches used to obtain propagating states and scattering matrices. We show that our algorithm is robust...journal article 2018
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de Vries, F.K. (author), Timmerman, Tom (author), Ostroukh, Viacheslav P. (author), van Veen, J. (author), Beukman, A.J.A. (author), Qu, F. (author), Wimmer, M.T. (author), Kiselev, Andrey A. (author), Kouwenhoven, Leo P. (author)Josephson junctions defined in strong spin orbit semiconductors are highly interesting for the search for topological systems. However, next to topological edge states that emerge in a sufficient magnetic field, trivial edge states can also occur. We study the trivial edge states with superconducting quantum interference measurements on...journal article 2018
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Skolasinski, R.J. (author), Pikulin, D. (author), Alicea, Jason (author), Wimmer, M.T. (author)We show that edge-state transport in semiconductor-based quantum spin Hall systems is unexpectedly robust to magnetic fields. The origin for this robustness lies in an intrinsic suppression of the edge-state g-factor and the fact that the edge-state Dirac point is typically hidden in the valence band. A detailed k·p band-structure analysis...journal article 2018
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de Vries, F.K. (author), Shen, J. (author), Skolasinski, R.J. (author), Nowak, M.P. (author), Varjas, D. (author), Wang, L. (author), Wimmer, M.T. (author), Zwanenburg, F.A. (author), Li, A. (author), Kölling, S. (author), Verheijen, M.P.A.M. (author), Bakkers, E.P.A.M. (author), Kouwenhoven, Leo P. (author)Low dimensional semiconducting structures with strong spin-orbit interaction (SOI) and induced superconductivity attracted great interest in the search for topological superconductors. Both the strong SOI and hard superconducting gap are directly related to the topological protection of the predicted Majorana bound states. Here we explore the...journal article 2018