We report the first experimental observation of a characteristic nonlinear threshold behavior from dc dynamical response as an evidence for a Wigner crystallization in high-purity GaAs 2D hole systems in zero magnetic field. The system under increasing current drive exhibits voltage oscillations with negative differential resistance. They confirm the coexistence of a moving crystal along with striped edge states as observed for electrons on helium surfaces. However, the threshold is well below the typical classical levels due to a different pinning and depinning mechanism that is possibly related to a quantum process.
@article{arxiv.1306.4196,
title = {Evidence for A Two-dimensional Quantum Wigner Solid in Zero Magnetic Field},
author = {Jian Huang and L. N. Pfeiffer and K. W. West},
journal= {arXiv preprint arXiv:1306.4196},
year = {2015}
}