We study nonperturbative interaction corrections to the thermodynamic quantities of multichannel disordered wires in the presence of the Coulomb interactions. Within the replica nonlinear σ -model (NLσM) formalism, they arise from nonperturbative soliton saddle points of the NLσM action. The problem is reduced to evaluating the partition function of a replicated classical one-dimensional Coulomb gas. The state of the latter depends on two parameters: the number of transverse channels in the wire Nch and the dimensionless conductance G (LT) of a wire segment of length equal to the thermal diffusion length LT. At relatively high temperatures, G (LT) ln Nch, the gas is dimerized, i.e., consists of bound neutral pairs. At lower temperatures, ln Nch G (LT) 1, the pairs overlap and form a Coulomb plasma. The crossover between the two regimes occurs at a parametrically large conductance G (LT) ∼ln Nch and may be studied independently from the perturbative effects. Specializing on the high-temperature regime, we obtain the leading nonperturbative correction to the wire heat capacity. Its ratio to the heat capacity for noninteracting electrons, C0, is δC C0 ∼ Nch G2 (LT) e-2G (LT).
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 6 Dec 2007|