Pseudo-ballistic transport in 3D topological insulator quantum wires

TL;DR

This paper uncovers a pseudo-ballistic transport regime in disordered 3D topological insulator quantum wires, where ballistic-like conductance persists beyond the mean free path, affecting conductance fluctuations.

Contribution

It introduces the concept of pseudo-ballistic transport in topological insulator nanowires, supported by experimental and theoretical evidence showing extended ballistic properties.

Findings

Pseudo-ballistic transport observed in Bi₂Se₃ nanoribbons.

Non-universal conductance fluctuations due to quasi-1D surface modes.

Pseudo-ballistic behavior persists over broad energy ranges.

Abstract

Quantum conductance fluctuations are investigated in disordered 3D topological insulator quantum wires. Both experiments and theory reveal a new transport regime in a mesoscopic conductor, pseudo-ballistic transport, for which ballistic properties persist beyond the transport mean free path, characteristic of diffusive transport. It results in non-universal conductance fluctuations due to quasi-1D surface modes, as observed in long and narrow Bi$_2$Se$_3$ nanoribbons. Spin helical Dirac fermions in quantum wires retain pseudo-ballistic properties over an unusually broad energy range, due to strong quantum confinement and weak momentum scattering.