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We report magneto-transport studies of topological insulator Bi_{2}Te_{3} thin films grown by pulsed laser deposition. A non-saturating linear-like magneto-resistance (MR) is observed at low temperatures in the magnetic field range from a…

Mesoscale and Nanoscale Physics · Physics 2013-01-18 S. X. Zhang , R. D. McDonald , A. Shekhter , Z. X. Bi , Y. Li , Q. X. Jia , S. T. Picraux

Topological insulators embody a new state of matter characterized entirely by the topological invariants of the bulk electronic structure rather than any form of spontaneously broken symmetry. Unlike the 2D quantum Hall or quantum…

Recently, it has been theoretically predicted that Cd3As2 is a three dimensional Dirac material, a new topological phase discovered after topological insulators, which exhibits a linear energy dispersion in the bulk with massless Dirac…

Mesoscale and Nanoscale Physics · Physics 2016-01-22 Bo Zhao , Peihong Cheng , Haiyang Pan , Shuai Zhang , Baigeng Wang , Guanghou Wang , Faxian Xiu , Fengqi Song

Topological insulators have been predicted to exhibit a variety of interesting phenomena including a quantized magnetoelectric response and novel spintronics effects due to spin textures on their surfaces. However, experimental observation…

Material defects remain as the main bottleneck to the progress of topological insulators (TIs). In particular, efforts to achieve thin TI samples with dominant surface transport have always led to increased defects and degraded mobilities,…

Motivated by the experimental difficulty to produce topological insulators (TIs) of the Bi$_2$Se$_3$ family with pure surface-state conduction, we study the effect that the bulk can have on the low-temperature transport properties of gated…

Mesoscale and Nanoscale Physics · Physics 2018-12-31 H. Velkov , G. N. Bremm , T. Micklitz , G. Schwiete

Optical band gap properties of high-quality few-layer topological insulator Bi2Se3 thin films grown with magnetron sputtering are investigated using broadband absorption spectroscopy. We provide direct optical evidence of a rigid blue-shift…

Materials Science · Physics 2017-05-24 Yub Raj Sapkota , Asma Alkabsh , Aaron Walber , Hassana Samassekou , Dipanjan Mazumdar

While evidence of a topologically nontrivial surface state has been identified in surface-sensitive measurements of Bi2Se3, a significant experimental concern is that no signatures have been observed in bulk transport. In a search for such…

The electronic ground state of a three-dimensional (3D) band insulator with time-reversal ($\Theta$) symmetry or time-reversal times a discrete translation ($\Theta T_{1/2}$) symmetry is classified by a $\mathbb{Z}_{2}$-valued topological…

Mesoscale and Nanoscale Physics · Physics 2024-10-23 Chao Lei , Perry T. Mahon , Allan H. MacDonald

It has been proposed that topological insulators can be best characterized not as surface conductors, but as bulk magnetoelectrics that -- under the right conditions-- have a universal quantized magnetoelectric response coefficient…

Mesoscale and Nanoscale Physics · Physics 2019-04-17 N. P. Armitage , Liang Wu

Strongly correlated Kondo insulator SmB6 is known for its peculiar low temperature residual conduction, which has recently been demonstrated to arise from a robust metallic surface state, as predicted by the theory of topological Kondo…

Strongly Correlated Electrons · Physics 2016-11-15 S. Thomas , D. J. Kim , S. B. Chung , T. Grant , Z. Fisk , Jing Xia

Artificial confinement of electrons by tailoring the layer thickness has turned out to be a powerful tool to harness control over competing phases in nano-layers of complex oxides. We investigate the effect of dimensionality on transport…

Strongly Correlated Electrons · Physics 2021-03-11 Subhadip Jana , Shwetha G. Bhat , B. C. Behera , L. Patra , P. S. Anil Kumar , B. R. K. Nanda , D. Samal

In the recently discovered class of materials known as topological insulators, the presence of strong spin-orbit coupling causes certain topological invariants in the bulk to differ from their values in vacuum. The sudden change of…

Topological insulators have been proposed to be best characterized as bulk magnetoelectric materials that show response functions quantized in terms of fundamental physical constants. Here we lower the chemical potential of…

Mesoscale and Nanoscale Physics · Physics 2016-12-07 Liang Wu , M. Salehi , N. Koirala , J. Moon , S. Oh , N. P. Armitage

In ideal topological insulator (TI) films the bulk state, which is supposed to be insulating, should not provide any electric coupling between the two metallic surfaces. However, transport studies on existing TI films show that the…

Materials Science · Physics 2014-10-21 Matthew Brahlek , Nikesh Koirala , Maryam Salehi , Namrata Bansal , Seongshik Oh

Bi2Se3 is an important semiconductor thermoelectric material and a prototype topological insulator. Here we report observation of Shubnikov-de Hass (SdH) oscillations accompanied by quantized Hall resistances (Rxy) in highly-doped n-type…

Strongly Correlated Electrons · Physics 2012-04-13 Helin Cao , Jifa Tian , Ireneusz Miotkowski , Tian Shen , Jiuning Hu , Shan Qiao , Yong P. Chen

We measure gate-tuned thermoelectric power of mechanically exfoliated Bi2Se3 thin films in the topological insulator regime. The sign of the thermoelectric power changes across the charge neutrality point as the majority carrier type…

Mesoscale and Nanoscale Physics · Physics 2015-03-12 Dohun Kim , Paul Syers , Nicholas P. Butch , Johnpierre Paglione , Michael S. Fuhrer

A large number of half-Heusler compounds have been recently proposed as three-dimensional (3D) topological insulators (TIs) with tunable physical properties.However, no transport measurements associated with the topological surface states…

Strongly Correlated Electrons · Physics 2014-08-08 Guizhou Xu , Wenhong Wang , Xiaoming Zhang , Yin Du , Enke Liu , Shouguo Wang , Guangheng Wu , Zhongyuan Liu , Xi Xiang Zhang

Several small-bandgap semiconductors are now known to have protected metallic surface states as a consequence of the topology of the bulk electron wavefunctions. The known "topological insulators" with this behavior include the important…

Mesoscale and Nanoscale Physics · Physics 2013-01-01 Pouyan Ghaemi , Roger Mong , Joel E. Moore

Topological insulator (TI) thin films with surface magnetism are expected to exhibit a quantized anomalous Hall effect (QAHE) when the magnetizations on the top and bottom surfaces are parallel, and a quantized topological magnetoelectric…

Mesoscale and Nanoscale Physics · Physics 2021-11-11 Nezhat Pournaghavi , Anna Pertsova , Allan H. MacDonald , Carlo Canali