Thermal broadening of the Coulomb blockade peaks in quantum Hall interferometers

Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences - 72 Tsarigradsko Chaussee, 1784 Sofia, Bulgaria, EU

^a lgeorg@inrne.bas.bg

Received: 30 June 2010
Accepted: 29 July 2010

Abstract

We demonstrate that the differential magnetic susceptibility of a fractional quantum Hall disk, representing a Coulomb island in a Fabry-Pérot interferometer, is exactly proportional to the island's conductance and its paramagnetic peaks are the equilibrium counterparts of the Coulomb blockade conductance peaks. Using as a thermodynamic potential the partition functions of the edge states' effective conformal field theory we find the positions of the Coulomb blockade peaks, when the area of the island is varied, the modulations of the distance between them as well as the thermal decay and broadening of the peaks when temperature is increased. The finite-temperature estimates of the peak's heights and widths could give important information about the experimental observability of the Coulomb blockade. In addition, the predicted peak asymmetry and displacement at finite temperature due to neutral multiplicities could serve to distinguish different fractional quantum Hall states with similar zero-temperature Coulomb blockade patterns.