Signature of pseudodiffusive transport in mesoscopic topological insulators

Open Access

Signature of pseudodiffusive transport in mesoscopic topological insulators

Saurav Islam, Semonti Bhattacharyya, Hariharan Nhalil, Suja Elizabeth, and Arindam Ghosh

Phys. Rev. Research 2, 033019 – Published 6 July 2020

Abstract

One of the unique features of Dirac Fermions is pseudodiffusive transport by evanescent modes at low Fermi energies when disorder is low. At higher Fermi energies, i.e., charge carrier densities, the electrical transport is diffusive in nature and the propagation occurs via plane waves. In this study, we report the detection of such evanescent modes in the surface states of topological insulator through $1 / f$ noise for the first time. While signatures of pseudodiffusive transport have been seen experimentally in graphene, such behavior is yet to be observed explicitly in any other system with a Dirac dispersion. To probe this, we have studied $1 / f$ noise in topological insulators as a function of gate voltage, and temperature. Our results show a nonmonotonic behavior in $1 / f$ noise as the gate voltage is varied, suggesting a crossover from pseudodiffusive to diffusive transport regime in mesoscopic topological insulators. The temperature dependence of noise points towards conductance fluctuations from quantum interference as the dominant source of the noise in these samples.

Received 11 January 2020
Accepted 3 June 2020

DOI:https://doi.org/10.1103/PhysRevResearch.2.033019

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society

Physics Subject Headings (PhySH)

Mesoscopics Noise Topological insulators

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Saurav Islam ^1,*, Semonti Bhattacharyya ^1,†,‡, Hariharan Nhalil¹, Suja Elizabeth¹, and Arindam Ghosh^1,2

¹Department of Physics, Indian Institute of Science, Bangalore 560012, India
²Centre for Nanoscience and Engineering, Indian Institute of Science, Bangalore 560012, India

^*isaurav@iisc.ac.in
^†Present address: School of Physics and Astronomy, Monash University, Victoria 3800, Australia.
^‡Present address: ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), Monash University, Monash, Victoria 3800, Australia.