Character of the phase transition at the two-dimensional electron-liquid-to-solid boundary.

Abstract

Nonlinear threshold electric transport has been studied at $T\ensuremath{\simeq}30$ mK near the collective insulating transition in a dilute two-dimensional (2D) electron system in high-mobility Si MOSFET's. We found that the threshold electric field becomes steplike at the critical density, both when $H=0$ and when $H\ensuremath{\ne}0$. This steplike onset indicates a weak first-order phase transition at the 2D electron-solid-to-liquid phase boundary.