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We review low and high field magnetotransport in 80 nm-thick strained HgTe, a material that belongs to the class of strong three-dimensional topological insulators. Utilizing a top gate, the Fermi level can be tuned from the valence band…

Mesoscale and Nanoscale Physics · Physics 2020-07-02 Johannes Ziegler , Dmitriy A. Kozlov , Nikolay N. Mikhailov , Sergey A. Dvoretsky , Dieter Weiss

We demonstrate evidences of electronic transport via topological Dirac surface states in a thin film of strained HgTe. At high perpendicular magnetic fields, we show that the electron transport reaches the quantum Hall regime with vanishing…

Mesoscale and Nanoscale Physics · Physics 2017-12-27 C. Thomas , O. Crauste , B. Haas , P. H. Jouneau , C. Bäuerle , L. P. Lévy , E. Orignac , D. Carpentier , P. Ballet , T. Meunier

Low energy excitation of surface states of a three-dimensional topological insulator (3DTI) can be described by Dirac fermions. By using a tight-binding model, the transport properties of the surface states in a uniform magnetic field is…

Mesoscale and Nanoscale Physics · Physics 2012-01-16 Yan-Yang Zhang , Xiang-Rong Wang , X. C. Xie

We report transport studies on a three dimensional, 70 nm thick HgTe layer, which is strained by epitaxial growth on a CdTe substrate. The strain induces a band gap in the otherwise semi-metallic HgTe, which thus becomes a three dimensional…

Mesoscale and Nanoscale Physics · Physics 2015-03-17 C. Brüne , C. X. Liu , E. G. Novik , E. M. Hankiewicz , H. Buhmann , Y. L. Chen , X. L. Qi , Z. X. Shen , S. C. Zhang , L. W. Molenkamp

We investigated the magnetotransport properties of strained, 80nm thick HgTe layers featuring a high mobility of mu =4x10^5 cm^2/Vs. By means of a top gate the Fermi-energy is tuned from the valence band through the Dirac type surface…

Mesoscale and Nanoscale Physics · Physics 2015-06-16 D. A. Kozlov , Z. D. Kvon , D. Weiss , E. B. Olshanetsky , N. N. Mikhailov , S. A. Dvoretsky

Topological insulators are a novel class of quantum matter with a gapped insulating bulk yet gapless spin helical Dirac fermion conducting surface states. Here, we report local and non-local electrical and magneto transport measurements in…

Mesoscale and Nanoscale Physics · Physics 2016-05-11 Yang Xu , Ireneusz Miotkowski , Yong P. Chen

Topological insulators can be seen as band-insulators with a conducting surface. The surface carriers are Dirac particles with an energy which increases linearly with momentum. This confers extraordinary transport properties characteristic…

Mesoscale and Nanoscale Physics · Physics 2011-12-12 Clément Bouvier , Tristan Meunier , Philippe Ballet , Xavier Baudry , Roman Bernd Günter Kramer , Laurent Lévy

Magneto-transport measurements on gated high mobility heterostructures containing a 60 nm layer of tensile strained HgTe, a three-dimensional topological insulator, show well-developed Hall quantization from surface states both in the n- as…

We have studied the fractional quantum Hall states on the surface of a topological insulator thin film in an external magnetic field, where the Dirac fermion nature of the charge carriers have been experimentally established only recently.…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 Vadim M. Apalkov , Tapash Chakraborty

We explore the scattering of Dirac electrons in a double-gated topological insulator in the presence of magnetic proximity effects and warped surface states. It is found that a magnetic field can shift the Dirac cone in momentum space and…

Mesoscale and Nanoscale Physics · Physics 2019-08-13 Masomeh Arabikhah , Alireza Saffarzadeh

The surface states of topological insulators, which behave as charged massless Dirac fermions, are studied in the presence of a quantizing uniform magnetic field. Using the method of D.H. Lee[1], analytical formula satisfied by the energy…

Mesoscale and Nanoscale Physics · Physics 2011-12-13 Oskar Vafek

We show that in the new topological-insulator compound Bi_{1.5}Sb_{0.5}Te_{1.7}Se_{1.3} one can achieve a surfaced-dominated transport where the surface channel contributes up to 70% of the total conductance. Furthermore, it was found that…

Materials Science · Physics 2011-07-28 A. A. Taskin , Zhi Ren , Satoshi Sasaki , Kouji Segawa , Yoichi Ando

Pulsed magnetic fields of up to 55T are used to investigate the transport properties of the topological insulator Bi_2Se_3 in the extreme quantum limit. For samples with a bulk carrier density of n = 2.9\times10^16cm^-3, the lowest Landau…

Mesoscale and Nanoscale Physics · Physics 2010-12-03 J. G. Analytis , R. D. McDonald , S. C. Riggs , J. -H. Chu , G. S. Boebinger , I. R. Fisher

It is well established that topological insulators sustain Dirac fermion surface states as a consequence of band inversion in the bulk. These states have a helical spin polarization and a linear dispersion with large Fermi velocity. In this…

Magnetic oscillations of Dirac surface states of topological insulators are expected to be associated with the formation of Landau levels or the Aharonov-Bohm effect. We instead study the conductance of Dirac surface states subjected to an…

Using THz spectroscopy in external magnetic fields we investigate the low-temperature charge dynamics of strained HgTe, a three dimensional topological insulator. From the Faraday rotation angle and ellipticity a complete characterization…

Strongly Correlated Electrons · Physics 2013-03-27 A. M. Shuvaev , G. V. Astakhov , G. Tkachov , C. Brüne , H. Buhmann , L. W. Molenkamp , A. Pimenov

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…

Mesoscale and Nanoscale Physics · Physics 2011-12-12 B. Sacepe , J. B. Oostinga , J. Li , A. Ubaldini , N. J. G. Couto , E. Giannini , A. F. Morpurgo

We measure the quantum capacitance and probe thus directly the electronic density of states of the high mobility, Dirac type of two-dimensional electron system, which forms on the surface of strained HgTe. Here we show that observed…

Mesoscale and Nanoscale Physics · Physics 2016-04-27 D. A. Kozlov , D. Bauer , J. Ziegler , R. Fischer , M. L. Savchenko , Z. D. Kvon , N. N. Mikhailov , S. A. Dvoretsky , D. Weiss

Recent experiments reveal that the strained bulk HgTe can be regard as a three-dimensional topological insulator (TI). Motivated by this, we explore the strain effects on the magnetotransport properties of the HgTe surface states at…

Mesoscale and Nanoscale Physics · Physics 2016-03-14 Ning Ma

Three-dimensional (3D) topological insulators (TIs) are known to carry 2D Dirac-like topological surface states in which spin-momentum locking prohibits backscattering. When thinned down to a few nanometers, the hybridization between the…

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