Theory of Native Orientational Pinning in Quantum Hall Nematics
arXiv:1307.5489
Abstract
The orientation of the electron-nematic states discovered in the quantum Hall regime of GaAs growth-direction quantum wells is pinned by a weak native source of anisotropy. In this Letter we explain that this property, which has remained mysterious over more than a decade of research, follows from the presence of both Rashba and Dresselhaus spin-orbit interactions. The hard transport direction of the nematic state is determined by the relative sign of the Rashba and Dresselhaus coefficients, and coincides with either the or the crystallographic direction. Our theoretical estimate of the pinning energy is in agreement with experimental studies of the competition between native pinning and intentional pinning by an in-plane magnetic field.
5 pages, 1 figure