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3D topological insulators
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Topological insulators constitute a new state of condensed matter wherein the combined effects of time-reversal symmetry and spin-orbit coupling leads to invariants that are robust with respect to disorder. A generic consequence is the appearance of gapless modes at the interface between a topological insulator and conventional insulators (such as the vacuum). We are exploring the physical properties of narrow band gap semiconductors that are candidates for achieving a 3D topological insulator. The principal aim is to synthesize model 3D topological insulators whose behavior is modified by the vicinal coupling to symmetry-breaking order parameters such as superconductivity and magnetism.

This research area provides opportunities for undergraduate research.

Publications

2010 · 2011 · 2012 · All
D. Zhang, A. R. Richardella, S. Xu, D. Rench, A. Kandala, T. Flanagan, H. Beidenkopf, A. L. Yeats, B. B. Buckley, P. V. Klimov, D. D. Awschalom, A. Yazdani, P. Schiffer, M. Hasan and N. Samarth, "Interplay between ferromagnetism, surface states, and quantum corrections in a magnetically doped topological insulator," Phys. Rev. B 86, 205127 (2012) Abstract/Comments
J. Wang, C. Chang, H. Li, K. He, D. Zhang, M. Singh, X. Ma, N. Samarth, M. Xie, Q. K. Xue and M. H. W. Chan, "Interplay between topological insulators and superconductors," Phys. Rev. B 85, 045415 (2012)
A. Kandala, A. R. Richardella, D. Rench, D. Zhang, T. Flanagan and N. Samarth, "Magneto-transport Signatures of a Magnetic Gap in Hybrid Topological Insulator-Ferromagnetic Insulator Heterostructure Devices", (2012) cond-mat/arxiv:1212.1225
S. Xu, M. Neupane, C. Liu, D. Zhang, A. R. Richardella, L. Wray, N. Alidoust, M. Leandersson, T. Balasubramanian, J. Sánchez-Barrig, O. Rader, G. Landolt, B. Slomski, J. Hugo Dil, J. Osterwalder, T. Chang, H. Jeng, H. Lin, A. Bansil, N. Samarth and M. Hasan, "Hedgehog spin texture and Berry’s phase tuning in a magnetic topological insulator," Nature Phys. 8, 616 – 622 (2012)
D. Zhang, J. Wang, A. DaSilva, J. Lee, H. R. Gutierrez, M. H. W. Chan, J. K. Jain and N. Samarth, "Superconducting proximity effect and possible evidence for Pearl vortices in a candidate topological insulator," Phys. Rev. B 84, 165120 (2011) Abstract/Comments
J. Wang, A. DaSilva, C. Chang, K. He, J. K. Jain, N. Samarth, X. Ma, Q. K. Xue and M. H. W. Chan, "Evidence for electron-electron interaction in topological insulator thin films," Phys. Rev. B 83, 245538 (2011)
A. R. Richardella, D. Zhang, J. Lee, D. Rench, A. Koser, A. L. Yeats, B. B. Buckley, D. D. Awschalom and N. Samarth, "Coherent Heteroepitaxy of Bi2Se3 on GaAs (111)B," Appl. Phys. Lett. 97, art. no. 262104 (2010)

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

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N. Samarth : 3D topological insulator heterostructures