Fluctuational internal Josephson effect in topological insulator film

TL;DR

This paper predicts a significant enhancement of tunneling conductivity in topological insulator films due to Cooper electron-hole pair fluctuations, exhibiting critical behavior near phase transitions, interpreted as a fluctuational internal Josephson effect.

Contribution

It introduces the concept of a fluctuational internal Josephson effect in topological insulator films, highlighting the critical behavior of tunneling conductivity near phase transitions due to electron-hole pair fluctuations.

Findings

Enhanced tunneling conductivity near critical temperature

Critical index =2 for phase transition behavior

Applicability to electron-hole bilayers

Abstract

Tunneling between opposite surfaces of topological insulator thin film populated by electrons and holes is considered. We predict considerable enhancement of tunneling conductivity by Cooper electron-hole pair fluctuations that are precursor of their Cooper pairing. Cooper pair fluctuations lead to the critical behavior of tunneling conductivity in vicinity of critical temperature with critical index \nu=2. If the pairing is suppressed by disorder the behavior of tunneling conductivity in vicinity of quantum phase transition is also critical with the index \mu=2. The effect can be interpreted as fluctuational internal Josephson effect and it is general phenomenon for electron-hole bilayers. The peculiarities of the effect in other realizations of electron-hole bilayer are discussed.