Quantum Depinning Transition of Quantum Hall Stripes

TL;DR

This paper investigates how disorder influences the electromagnetic response of quantum Hall stripes, revealing a depinning transition characterized by a shift from a pinned state to a sliding state along the stripes, akin to a Kosterlitz-Thouless transition.

Contribution

It introduces a theoretical model demonstrating a depinning transition in quantum Hall stripes using elastic theory, replicas, and Gaussian variational methods, highlighting a novel phase transition.

Findings

Existence of a depinning transition at a critical filling factor

Resonant peaks in conductivity shift to zero at transition

Partial RSB phase with sliding only along stripe direction

Abstract

We examine the effect of disorder on the electromagnetic response of quantum Hall stripes using an effective elastic theory to describe their low-energy dynamics, and replicas and the Gaussian variational method to handle disorder effects. Within our model we demonstrate the existence of a depinning transition at a critical partial Landau level filling factor $\Delta\nu_c$. For $\Delta\nu<\Delta\nu_c$, the pinned state is realized in a replica symmetry breaking (RSB) solution, and the frequency-dependent conductivities in both perpendicular and parallel to the stripes show resonant peaks. These peaks shift to zero frequency as $\Delta\nu\to \Delta\nu_c$. For $\Delta\nu\ge\Delta\nu_c$, we find a {\em partial RSB (PRSB)} solution in which there is free sliding only along the stripe direction. The transition is analogous to the Kosterlitz-Thouless phase transition.