Impact of the modulation doping layer on the \nu=5/2 anisotropy

TL;DR

This study investigates how the distance of the modulation doping layer affects the anisotropic electronic transport at the =5/2 Landau level in GaAs quantum wells under tilted magnetic fields, revealing the doping layer's significant influence.

Contribution

It provides a systematic analysis of the impact of modulation doping layer setback distance on =5/2 anisotropy in high-quality GaAs quantum wells, highlighting the doping layer's role.

Findings

Transport anisotropy depends on setback distance d.

Anisotropy varies with in-plane magnetic field orientation.

Doping layer distance influences the =5/2 anisotropic behavior.

Abstract

We have carried out a systematic study of the tilted magnetic field induced anisotropy at the Landau level filling factor \nu=5/2 in a series of high quality GaAs quantum wells, where the setback distance (d) between the modulation doping layer and the GaAs quantum well is varied from 33 to 164 nm. We have observed that in the sample of the smallest d electronic transport is anisotropic when the in-plane magnetic field (B_{ip}) is parallel to the [1-10] crystallographic direction, but remains more or less isotropic when B_{ip} // [110]. In contrast, in the sample of largest d, electronic transport is anisotropic in both crystallographic directions. Our results clearly show that the modulation doping layer plays an important role in the tilted field induced \nu=5/2 anisotropy.