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Topological insulators are ideally represented as having an insulating bulk with topologically protected, spin-textured surface states. However, it is increasingly becoming clear that these surface transport channels can be accompanied by a…

Mesoscale and Nanoscale Physics · Physics 2017-07-28 E. K. de Vries , S. Pezzini , M. J. Meijer , N. Koirala , M. Salehi , J. Moon , S. Oh , S. Wiedmann , T. Banerjee

We reanalyze some of the critical transport experiments and provide a coherent understanding of the current generation of topological insulators (TIs). Currently TI transport studies abound with widely varying claims of the surface and bulk…

Materials Science · Physics 2015-06-18 Matthew Brahlek , Nikesh Koirala , Namrata Bansal , Seongshik Oh

Granular conductors form an artificially engineered class of solid state materials wherein the microstructure can be tuned to mimic a wide range of otherwise inaccessible physical systems. At the same time, topological insulators (TIs) have…

Materials Science · Physics 2017-06-05 Abhishek Banerjee , Oindrila Deb , Kunjalata Majhi , R. Ganesan , Diptiman Sen , P. S. Anil Kumar

We demonstrate the ability to reduce the carrier concentration of thin films of the topological insulator (TI) Bi2Se3 by utilizing a novel approach, namely non-volatile electrostatic gating via corona charging of electret polymers.…

Mesoscale and Nanoscale Physics · Physics 2018-04-11 R. M. Ireland , Liang Wu , M. Salehi , S. Oh , N. P. Armitage , H. E. Katz

We describe the characterization of structural defects that occur during molecular beam epitaxy of topological insulator thin films on commonly used substrates. Twinned domains are ubiquitous but can be reduced by growth on smooth InP…

Materials Science · Physics 2015-07-13 Anthony Richardella , Abhinav Kandala , Joon Sue Lee , Nitin Samarth

We study transport across either a potential or a magnetic barrier which is placed on the top surface of a three-dimensional thin topological insulator (TI). For such thin TIs, the top and bottom surfaces interact via a coupling $\lambda$…

Mesoscale and Nanoscale Physics · Physics 2018-11-28 Adithi Udupa , K. Sengupta , Diptiman Sen

We report transport measurements on Josephson junctions consisting of Bi2Te3 topological insulator (TI) thin films contacted by superconducting Nb electrodes. For a device with junction length L = 134 nm, the critical supercurrent Ic can be…

Asymmetric electrical conductance is theoretically demonstrated on the surface of a topological insulator (TI) in the limit of infinitesimally small forward and reverse biases between two spin selective electrodes. The discontinuous…

Mesoscale and Nanoscale Physics · Physics 2015-09-16 Xiaopeng Duan , Xi-Lai Li , Yuriy G. Semenov , Ki Wook Kim

Superconducting-proximity topological insulators (STIs) have garnered significant research attention over the past two decades. In this Letter, we demonstrate that a low-dimensional STI in the topological-nontrivial phase (TP) exhibits an…

Superconductivity · Physics 2024-09-02 Yajiang Chen , Ke-Ji Chen , Jia-Ji Zhu , A. A. Shanenko

The performance of GaN-on-Silicon electronic devices is severely degraded by the presence of a parasitic conduction pathway at the nitride-substrate interface which contributes to switching losses and lower breakdown voltages. The physical…

We investigate the effects of magnetic and nonmagnetic impurities on the two-dimensional surface states of three-dimensional topological insulators (TIs). Modeling weak and strong TIs using a generic four-band Hamiltonian, which allows for…

Mesoscale and Nanoscale Physics · Physics 2016-02-26 Andreas Pieper , Holger Fehske

Topological insulators are insulating in the bulk but possess spin-momentum locked metallic surface states protected by time-reversal symmetry. The existence of these surface states has been confirmed by angle-resolved photoemission…

Materials Science · Physics 2012-11-09 Jian Wang , Handong Li , Cui-Zu Chang , Ke He , Joon Sue Lee , Xu-Cun Ma , Nitin Samarth , Qi-Kun Xue , Maohai Xie , M. H. W. Chan

The local conductivity in the channel of a thin-film field-effect transistor is proportional to the charge density induced by the local gate voltage. We show how this determines the frequency- and position-dependence of the charge induced…

Materials Science · Physics 2015-06-05 E. G. Bittle , J. W. Brill , J. P. Straley

Bi$_{2}$Te$_{3}$ and Bi$_{2}$Se$_{3}$ are well known 3D-topological insulators. Films made of these materials exhibit metal-like surface states with a Dirac dispersion and possess high mobility. The high mobility metal-like surface states…

Mesoscale and Nanoscale Physics · Physics 2015-06-22 Parijat Sengupta , Tillmann Kubis , Yaohua Tan , Gerhard Klimeck

The recent emergence of topological insulators (TI) has spurred intensive efforts to grow TI thin films on various substrates. However, little is known about how robust the topological surface states (TSS) are against disorders and other…

We propose a minimal tight-binding model for thin films made of topological crystalline insulator (TCI) on the basis of the mirror and discrete rotational symmetries. The basic term consists of the spin-orbit interaction describing a Weyl…

Mesoscale and Nanoscale Physics · Physics 2014-07-02 Motohiko Ezawa

Topological crystalline insulators represent a new state of matter, in which the electronic transport is governed by mirror-symmetry protected Dirac surface states. Due to the helical spin-polarization of these surface states, the proximity…

We analytically calculate the intra- and inter-surface dynamical density-density linear responses of ultra-thin topological insulator films with finite tunneling between their top and bottom surfaces in both metallic and insulating regimes.…

Mesoscale and Nanoscale Physics · Physics 2020-03-10 Moslem Mir , Saeed H. Abedinpour

Topological Insulators (TIs) exhibit exciting optical properties, which opens up a new pathway to generate ultrashort pulses from fiber lasers. Layered TIs display distinct saturable absorption property due to excited state absorption, as…

Materials Science · Physics 2021-05-20 Shyamal Mondal , Rounak Ganguly , Krishnakanta Mondal

Compensation of intrinsic charges is widely used to reduce the bulk conductivity of 3D topological insulators (TIs). Here we use low temperature electron irradiation-induced defects paired with in-situ electrical transport measurements to…

Materials Science · Physics 2016-09-27 C. W. Rischau , A. Ubaldini , E. Giannini , C. J. van der Beek