Field-tilt Anisotropy Energy in Quantum Hall Stripe States

TL;DR

This paper investigates how a tilted magnetic field influences the orientation energy of unidirectional charge density wave states in quantum Hall systems, explaining experimental anisotropy and predicting new stripe orientations.

Contribution

The study provides detailed Hartree-Fock calculations of tilt-induced anisotropy energy, clarifying stripe orientation behavior and predicting new states in wider systems.

Findings

Stripes are oriented perpendicular to the in-plane field in current samples.

Tilt-induced stripe states with variable anisotropy energy sign are predicted for wider systems.

Experimental observations are consistent with the calculated stripe orientations.

Abstract

Recently reported giant anisotropy in the longitudinal resistivity of a 2D electron system with valence Landau level index $N \ge 2$ has been interpreted as a signal of unidirectional charge density wave (UCDW) ground states. We report on detailed Hartree-Fock calculations of the UCDW orientation energy induced by a tilted magnetic field. We find that for current experimental samples stripes are oriented perpendicular to the in-plane field, consistent with experiment. For wider 2D electron systems we predict tilt-induced stripe states with variable anisotropy energy sign.