Coherent Transport in a Homojunction between an Excitonic Insulator and Semimetal

Massimo Rontani and L. J. Sham

Phys. Rev. Lett. 94, 186404, 2005

DOI: https://doi.org/10.1103/PhysRevLett.94.186404

From the solution of a two-band model, we predict that the thermal and electrical transport across the junction of a semimetal and an excitonic insulator will exhibit high resistance behavior and low entropy production at low temperatures, distinct from a junction of a semimetal and a normal semiconductor. This phenomenon, ascribed to the dissipationless exciton flow which dominates over the charge transport, is based on the much longer length scale of the change of the effective interface potential for electron scattering due to the coherence of the condensate than in the normal state.