Critical fluctuations and conduction at the Fermi level in expanded fluid mercury

Abstract

An explanation is proposed for the transport properties of expanded supercritical mercury in the low-density regime near the critical point. In particular, it is suggested that the energy barriers to conduction at the Fermi level diminish as the critical point is approached and that the conduction mechanism changes from excitation to the mobility edge to transport at the Fermi level near the minimum of the density of states. This mechanism is a possible explanation for the observed vanishing of the thermopower in the vicinity of the critical point.