Observations of a glass transition in a quasi–two-dimensional electron-hole system

Fachbereich Physik und Wiss. Zentrum für Materialwissenschaften Philipps-Universität Marburg, Renthof 5 - D-35032 Marburg, Germany

Received: 21 June 1999
Accepted: 30 August 1999

Abstract

Using time-resolved photoluminescence experiments and Monte Carlo simulation, we identify two distinct temperature regimes in the energy relaxation of excitons in a GaAs/AlGaAs double quantum structure. Below a critical temperature the system is glassy and exhibits slow, nonexponential energy relaxation to the longest times observed. At higher temperatures, the system achieves thermal equilibrium in finite time. The transition between these regimes is marked by a dramatic critical behavior: a dynamical broadening of the energy distribution at the glass temperature. Simulations reproduce this critical behavior and allow for the first time the determination of the density of localized states.