Scanning tunneling microscopy and spectroscopy on strong spin-orbit coupling chalcogenides

Shekhar Das; Anshu Sirohi; Gaurav Kumar Gupta; Suman Kamboj; Aastha Vasdev; Sirshendu Gayen; Prasenjit Guptasarma; Tanmoy Das; Goutam Sheet

Scanning tunneling microscopy and spectroscopy on strong spin-orbit coupling chalcogenides

ORAL

Abstract

A large number of A₂B₃ type chalcogenides with strong spin-orbit coupling like Bi₂Se₃, Bi₂Te₃, and Sb₂Te₃ etc. are topological insulators (TI) whereas Sb₂Se₃ is an exception in this group. In this talk, I will show, as the TI Bi₂Se₃, Sb₂Se₃ displays generation of highly spin-polarized current by point contact Andreev reflection spectroscopy. However, unlike in Bi₂Se₃, in case of Sb₂Se₃, a prominent quasiparticle interference (QPI) pattern could be observed in STM conductance mapping which contradicts the above experiment. According to the band structure calculation, there are two trivial surface states available and among them, one shows large splitting due to Rashba type spin-orbit coupling. In addition, we observe a large negative and anisotropic magnetoresistance in Sb₂Se₃. Experimental data reveal Sb₂Se₃ to be a trivial band insulator under ambient conditions with high spin-polarization due to Rashba type spin-orbit coupling.

March 7, 2019, 11:51 AM – March 7, 2019, 12:03 PM

Presenters

Shekhar Das

Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Indian Institute of Science Education and Research, Mohali

Authors

Shekhar Das

Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Indian Institute of Science Education and Research, Mohali
Anshu Sirohi

Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Indian Institute of Science Education and Research, Mohali
Gaurav Kumar Gupta

Department of Physics, IISc Bangalore
Suman Kamboj

Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Indian Institute of Science Education and Research, Mohali
Aastha Vasdev

Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Indian Institute of Science Education and Research, Mohali
Sirshendu Gayen

Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Indian Institute of Science Education and Research, Mohali
Prasenjit Guptasarma

Department of Physics, University of Wisconsin Milwaukee, Wisconsin 53211, Department of Physics, University of Wisconsin, Milwaukee, Department of Physics, University of Wisconsin Milwaukee, Wisconsin
Tanmoy Das

Department of Physics, IISc Bangalore, Indian Institute of Science, Bangalore, Physics, Indian Institute of Science
Goutam Sheet

Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Indian Institute of Science Education and Research, Mohali