Quantum Transport and Nano Angle-resolved Photoemission Spectroscopy on the Topological Surface States of Single Sb2Te3 Nanowires

Abstract

We report on low-temperature transport and electronic band structure of p-type Sb2Te3 nanowires, grown by chemical vapor deposition. Magnetoresistance measurements unravel quantum interference phenomena, which depend on the cross-sectional dimensions of the nanowires. The observation of periodic Aharonov-Bohm-type oscillations is attributed to transport in topologically protected surface states in the Sb2Te3 nanowires. The study of universal conductance fluctuations demonstrates coherent transport along the Aharonov-Bohm paths encircling the rectangular cross-section of the nanowires. We use nanoscale angle-resolved photoemission spectroscopy on single nanowires (nano-ARPES) to provide direct experimental evidence on the nontrivial topological character of those surface states. The compiled study of the bandstructure and the magnetotransport response unambiguosly points out the presence of topologically protected surface states in the nanowires and their substantial contribution to the quantum transport effects, as well as the hole doping and Fermi velocity among other key issues. The results are consistent with the theoretical description of quantum transport in intrinsically doped quasi-one-dimensional topological insulator nanowires.

Magnetotransport signatures of three-dimensional topological insulator nanostructures

“…Furthermore, these surface states have been probed directly, using, e.g., nano-ARPES or Kelvin probe microscopy techniques. 28,30,31 There is a solid understanding of uniaxial 3D TI nanowire (or ribbon) surface states in the presence of a magnetic field and different approaches have been introduced to model this system, e.g., effective and continuous (Dirac-like) surface models, [32][33][34][35] surface and bulk lattice models 36,37 and a Luttinger liquid description in the 1D limit. 38 Here, we extend these efforts to other 3D TI nanostructures, such as kinks or junctions, which have been proposed as the basic building blocks of 3D TI nanowire circuits for Majorana-based quantum information processing, for example.…”

Angle-resolved photoemission spectroscopy and its application to topological materials

“…Spatially resolved ARPES has been applied to the study of electronic structure of microscale and nanoscale materials and domains, including heterostructures 52,53,[216][217][218][219][220][221][222][223] , Sb 2 Te 3 nanowires 224,225 and the weak topological insulator β-Bi 4 I 4 (ref. 54 ).…”

Proximity‐Effect‐Induced Superconductivity in Nb/Sb2Te3‐Nanoribbon/Nb Junctions

“…[31,32] In magnetotransport the presence of these closedloop states manifest themselves by the appearance of Aharonov-Bohm type oscillations. [33][34][35][36][37][38] Recently, we fabricated normalmetal-contacted Au/Sb 2 Te 3 -NR/Au devices and investigated the electrical band structure and quantum transport using a quasi four-terminal current driven measurement scheme. [38] Specifically, the topologically protected surface states in the intrinsical p-type Sb 2 Te 3 NRs were confirmed by nanoscale angle-resolved photoemission spectroscopy.…”