The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
H Hilgenkamp - One of the best experts on this subject based on the ideXlab platform.
-
josephson supercurrent through a topological insulator surface State supplementary information
Nature Materials, 2013Co-Authors: Marinus Veldhorst, M Hoek, T Gang, V K Guduru, Van Der W G Wiel, Maaike Snelder, Alexandre Avraamovitch Golubov, Xiaolin Wang, U Zeitler, H HilgenkampAbstract:The long-sought yet elusive Majorana fermion1 is predicted to arise from a combination of a superconductor and a topological insulator. An essential step in the hunt for this emergent particle is the unequivocal observation of supercurrent in a topological phase. Here, direct evidence for Josephson supercurrents in superconductor (Nb)–topological insulator (Bi2Te3)–superconductor electron-beam fabricated junctions is provided by the observation of clear Shapiro steps under microwave irradiation, and a Fraunhofer-type dependence of the critical current on magnetic field. Shubnikov–de Haas oscillations in magnetic fields up to 30 T reveal a topologically non-trivial two-dimensional surface State. This surface State is attributed to mediate the ballistic Josephson current despite the fact that the normal State Transport is dominated by diffusive bulk conductivity. The lateral Nb–Bi2Te3–Nb junctions hence provide prospects for the realization of devices supporting Majorana fermions
-
josephson supercurrent through a topological insulator surface State
Nature Materials, 2012Co-Authors: Marinus Veldhorst, M Hoek, T Gang, V K Guduru, W. G. Van Der Wiel, Maaike Snelder, Alexandre Avraamovitch Golubov, Xiaolin Wang, U Zeitler, H HilgenkampAbstract:The long-sought yet elusive Majorana fermion(1) is predicted to arise from a combination of a superconductor and a topological insulator(2-4). An essential step in the hunt for this emergent particle is the unequivocal observation of supercurrent in a topological phase. Here, direct evidence for Josephson supercurrents in superconductor (Nb)-topological insulator (Bi2Te3)-superconductor electron-beam fabricated junctions is provided by the observation of clear Shapiro steps under microwave irradiation, and a Fraunhofer-type dependence of the critical current on magnetic field. Shubnikov-de Haas oscillations in magnetic fields up to 30 T reveal a topologically non-trivial two-dimensional surface State. This surface State is attributed to mediate the ballistic Josephson current despite the fact that the normal State Transport is dominated by diffusive bulk conductivity. The lateral Nb-Bi2Te3-Nb junctions hence provide prospects for the realization of devices supporting Majorana fermions(5).
L W Molenkamp - One of the best experts on this subject based on the ideXlab platform.
-
dirac screening stabilized surface State Transport in a topological insulator
Physical Review X, 2014Co-Authors: Christoph Brune, Cornelius Thienel, Michael Stuiber, Jan Bottcher, H Buhmann, E G Novik, Chaoxing Liu, Ewelina M Hankiewicz, L W MolenkampAbstract:New experimental results show that HgTe functions as a superb three-dimensional topological insulator over a range of applied gate voltages and that the screening of the Dirac surface States stabilizes surface conduction.
-
dirac screening stabilized surface State Transport in a topological insulator
arXiv: Mesoscale and Nanoscale Physics, 2014Co-Authors: Christoph Brune, Cornelius Thienel, Michael Stuiber, Jan Bottcher, H Buhmann, E G Novik, Chaoxing Liu, Ewelina M Hankiewicz, L W MolenkampAbstract:We report magnetoTransport studies on a gated strained HgTe device. This material is a threedimensional topological insulator and exclusively shows surface State Transport. Remarkably, the Landau level dispersion and the accuracy of the Hall quantization remain unchanged over a wide density range ($3 \times 10^{11} cm^{-2} < n < 1 \times 10^{12} cm^{-2}$). This implies that even at large carrier densities the Transport is surface State dominated, where bulk Transport would have been expected to coexist already. Moreover, the density dependence of the Dirac-type quantum Hall effect allows to identify the contributions from the individual surfaces. A $k \cdot p$ model can describe the experiments, but only when assuming a steep band bending across the regions where the topological surface States are contained. This steep potential originates from the specific screening properties of Dirac systems and causes the gate voltage to influence the position of the Dirac points rather than that of the Fermi level.
Marinus Veldhorst - One of the best experts on this subject based on the ideXlab platform.
-
josephson supercurrent through a topological insulator surface State supplementary information
Nature Materials, 2013Co-Authors: Marinus Veldhorst, M Hoek, T Gang, V K Guduru, Van Der W G Wiel, Maaike Snelder, Alexandre Avraamovitch Golubov, Xiaolin Wang, U Zeitler, H HilgenkampAbstract:The long-sought yet elusive Majorana fermion1 is predicted to arise from a combination of a superconductor and a topological insulator. An essential step in the hunt for this emergent particle is the unequivocal observation of supercurrent in a topological phase. Here, direct evidence for Josephson supercurrents in superconductor (Nb)–topological insulator (Bi2Te3)–superconductor electron-beam fabricated junctions is provided by the observation of clear Shapiro steps under microwave irradiation, and a Fraunhofer-type dependence of the critical current on magnetic field. Shubnikov–de Haas oscillations in magnetic fields up to 30 T reveal a topologically non-trivial two-dimensional surface State. This surface State is attributed to mediate the ballistic Josephson current despite the fact that the normal State Transport is dominated by diffusive bulk conductivity. The lateral Nb–Bi2Te3–Nb junctions hence provide prospects for the realization of devices supporting Majorana fermions
-
josephson supercurrent through a topological insulator surface State
Nature Materials, 2012Co-Authors: Marinus Veldhorst, M Hoek, T Gang, V K Guduru, W. G. Van Der Wiel, Maaike Snelder, Alexandre Avraamovitch Golubov, Xiaolin Wang, U Zeitler, H HilgenkampAbstract:The long-sought yet elusive Majorana fermion(1) is predicted to arise from a combination of a superconductor and a topological insulator(2-4). An essential step in the hunt for this emergent particle is the unequivocal observation of supercurrent in a topological phase. Here, direct evidence for Josephson supercurrents in superconductor (Nb)-topological insulator (Bi2Te3)-superconductor electron-beam fabricated junctions is provided by the observation of clear Shapiro steps under microwave irradiation, and a Fraunhofer-type dependence of the critical current on magnetic field. Shubnikov-de Haas oscillations in magnetic fields up to 30 T reveal a topologically non-trivial two-dimensional surface State. This surface State is attributed to mediate the ballistic Josephson current despite the fact that the normal State Transport is dominated by diffusive bulk conductivity. The lateral Nb-Bi2Te3-Nb junctions hence provide prospects for the realization of devices supporting Majorana fermions(5).
Chaoxing Liu - One of the best experts on this subject based on the ideXlab platform.
-
giant anisotropic magnetoresistance in a quantum anomalous hall insulator
Nature Communications, 2015Co-Authors: Abhinav Kandala, Chaoxing Liu, A Richardella, Susan Kempinger, N SamarthAbstract:When a three-dimensional ferromagnetic topological insulator thin film is magnetized out-of-plane, conduction ideally occurs through dissipationless, one-dimensional (1D) chiral States that are characterized by a quantized, zero-field Hall conductance. The recent realization of this phenomenon, the quantum anomalous Hall effect, provides a conceptually new platform for studies of 1D Transport, distinct from the traditionally studied quantum Hall effects that arise from Landau level formation. An important question arises in this context: how do these 1D edge States evolve as the magnetization is changed from out-of-plane to in-plane? We examine this question by studying the field-tilt-driven crossover from predominantly edge-State Transport to diffusive Transport in Crx(Bi,Sb)(2-x)Te3 thin films. This crossover manifests itself in a giant, electrically tunable anisotropic magnetoresistance that we explain by employing a Landauer-Buttiker formalism. Our methodology provides a powerful means of quantifying dissipative effects in temperature and chemical potential regimes far from perfect quantization.
-
dirac screening stabilized surface State Transport in a topological insulator
Physical Review X, 2014Co-Authors: Christoph Brune, Cornelius Thienel, Michael Stuiber, Jan Bottcher, H Buhmann, E G Novik, Chaoxing Liu, Ewelina M Hankiewicz, L W MolenkampAbstract:New experimental results show that HgTe functions as a superb three-dimensional topological insulator over a range of applied gate voltages and that the screening of the Dirac surface States stabilizes surface conduction.
-
dirac screening stabilized surface State Transport in a topological insulator
arXiv: Mesoscale and Nanoscale Physics, 2014Co-Authors: Christoph Brune, Cornelius Thienel, Michael Stuiber, Jan Bottcher, H Buhmann, E G Novik, Chaoxing Liu, Ewelina M Hankiewicz, L W MolenkampAbstract:We report magnetoTransport studies on a gated strained HgTe device. This material is a threedimensional topological insulator and exclusively shows surface State Transport. Remarkably, the Landau level dispersion and the accuracy of the Hall quantization remain unchanged over a wide density range ($3 \times 10^{11} cm^{-2} < n < 1 \times 10^{12} cm^{-2}$). This implies that even at large carrier densities the Transport is surface State dominated, where bulk Transport would have been expected to coexist already. Moreover, the density dependence of the Dirac-type quantum Hall effect allows to identify the contributions from the individual surfaces. A $k \cdot p$ model can describe the experiments, but only when assuming a steep band bending across the regions where the topological surface States are contained. This steep potential originates from the specific screening properties of Dirac systems and causes the gate voltage to influence the position of the Dirac points rather than that of the Fermi level.
Hongtao He - One of the best experts on this subject based on the ideXlab platform.
-
magnetoresistance anomaly in topological kondo insulator smb6 nanowires with strong surface magnetism
Advanced Science, 2018Co-Authors: Xingshuai He, Zongzheng Du, Bicong Ye, Liang Zhou, Yuan Tian, Shaozhi Deng, Haizhou Lu, Hongtao HeAbstract:: Topological Kondo insulators (TKIs) are a new class of topological materials in which topological surface States dominate the Transport properties at low temperatures. They are also an ideal platform for studying the interplay between strong electron correlations and topological order. Here, hysteretic magnetoresistance (MR) is observed in TKI SmB6 thin nanowires at temperatures up to 8 K, revealing the strong magnetism at the surface of SmB6. It is also found that such MR anomaly exhibits an intriguing finite size effect and only appears in nanowires with diameter smaller than 58 nm. These nontrivial phenomena are discussed in terms of the latest Kondo breakdown model, which incorporates the RKKY magnetic interaction mediated by surface States with the strong electron correlation in SmB6. It would provide new insight into the nature of TKI surface States. Additionally, a non-monotonically temperature dependent positive magnetoresistance is observed at intermediate temperatures, suggesting the possible impurity-band conduction in SmB6, other than the surface State Transport at low temperatures and the bulk-band Transport at high temperatures.
