# Signature of pseudo-diffusive transport in mesoscopic topological insulators

## TL;DR

This paper detects pseudo-diffusive transport in topological insulators via 1/f noise measurements, revealing a crossover from pseudo-diffusive to diffusive regimes and highlighting quantum interference effects.

## Contribution

First experimental observation of pseudo-diffusive transport signatures in topological insulators using 1/f noise analysis.

## Key findings

- Non-monotonic 1/f noise behavior with gate voltage indicating transport regime crossover
- Temperature dependence suggests conductance fluctuations from quantum interference
- Evidence of evanescent modes in surface states of topological insulators

## Abstract

One of the unique features of Dirac Fermions is pseudo-diffusive transport by evanescent modes at low Fermi energies when the disorder is low. At higher Fermi energies i.e. 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. While signatures of pseudo-diffusive 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 non-monotonic behavior in 1=f noise as the Fermi energy is varied, suggesting a crossover from pseudo-diffusive 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.