The anisotropic conductivity of two-dimensional electrons on a half-filled high Landau level

TL;DR

This paper investigates how unidirectional charge-density wave states in half-filled high Landau levels cause anisotropic conductivity, with theoretical results matching experimental observations near the transition temperature.

Contribution

It provides a theoretical analysis of anisotropic conductivity in 2D electrons on high Landau levels, highlighting the role of charge-density wave correlations.

Findings

Anisotropic corrections are proportional to (T_c - T)/T_c below T_c.

Above T_c, corrections scale with sqrt(T_c/(T - T_c)).

Results align with experimental data.

Abstract

We study the conductivity of two-dimensional interacting electrons on the half-filled $N$th Landau level with $N \gg 1$ in the presence of the quenched disorder. The existence of the unidirectional charge-density wave state at temperature $T<T_c$, where $T_c$ is the transition temperature, leads to the anisotropic conductivity tensor. We find that the leading anisotropic corrections are proportional to $(T_c-T)/T_c$ just below the transition in accordance with the experimental findings. Above $T_c$ the correlations corresponding to the unidirectional charge-density wave state below $T_c$ result in the corrections to the conductivity proportional to $\sqrt{T_c/(T-T_c)}$.