Spontaneous decay of metastable states in orthorhombic TaS3

High-accuracy, long-time dc conductivity measurements were performed at fixed temperatures. The conductivity corresponding to a metastable state created by a quick heat treatment was found to be time dependent on the time domain of 10-105 sec. A logarithmic expression describes the time dependence in the entire temperature range investigated (100K<T<150K). A simple model, based on the analogy with spin-glasses, is proposed. The possible role of low-energy excitations and infrared divergences is also discussed.