Strongly Anisotropic Electronic Transport at Landau Level Filling Factor $\nu = 9/2$ and $\nu = 5/2$ Under Tilted Magnetic Field

TL;DR

This study explores how tilted magnetic fields influence electronic transport anisotropy at specific Landau level fillings, revealing reorientation and induction of anisotropic phases in a two-dimensional electron system.

Contribution

It demonstrates that in-plane magnetic fields can reorient or induce anisotropic electronic phases at Landau level fillings $ u$ = 5/2, 7/2, 9/2, and 11/2, providing new insights into quantum Hall states.

Findings

In-plane magnetic field reorients anisotropic phases at $ u$=9/2 and 11/2.

In-plane magnetic field induces anisotropy at $ u$=5/2 and 7/2.

High resistance axis aligns with the in-plane magnetic field direction.

Abstract

We have investigated the influence of an increasing in-plane magnetic field on the states at half-filling of Landau levels ($\nu$ = 11/2, 9/2, 7/2, and 5/2) of a two-dimensional electron system. In the electrically anisotropic phase at $\nu$ = 9/2 and 11/2 an in-plane magnetic field of $\sim$ 1-2 T overcomes its initial pinning to the crystal lattice and {\it reorient} this phase. In the initially isotropic phases at $\nu$ = 5/2 and 7/2 an in-plane magnetic field {\it induces} a strong electrical anisotropy. In all cases, for high in-plane fields, the high resistance axis is parallel to the direction of the in-plane field.