Evidence for a liquid crystal phase transition in two-dimensional electrons in high Landau levels

Transport measurements of high-mobility two-dimensional electron systems at low temperatures have revealed a large resistance anisotropy around half-filling of excited Landau levels. These results have been attributed to electronic stripe-phase formation with spontaneously broken orientational symmetry. Mechanisms which are known to br ak the orientational symmetry include poorly-understood crystal structure effects and an inplane magnetic field, B∥. Here we report that a large B∥ also causes the transport anisotropy to persist up to much higher temperatures. In this regime, we find that the anisotropic resistance scales sublinearly with B∥ /T. These observations support the proposal that the transition from anisotropic to isotropic transport reflects a liquid crystal phase transition where local stripe order persists even in the isotropic regime.