title: Thermal enhancement of interference effects in quantum point contacts.
abstract: We study an electron interferometer formed with a quantum point contact and a scanning probe tip in a two-dimensional electron gas. The images giving the conductance as a function of the tip position exhibit fringes spaced by half the Fermi wavelength. For a contact opened at the edges of a quantized conductance plateau, the fringes are enhanced as the temperature T increases and can persist beyond the thermal length l(T). This unusual effect is explained by assuming a simplified model: The fringes are mainly given by a contribution which vanishes when T→0 and has a decay characterized by a T-independent scale.
authors.affiliation: Service de Physique de l'État Condensé (CNRS URA 2464), IRAMIS/SPEC, CEA Saclay, 91191 Gif-sur-Yvette, France.
authors.forename: Adel
authors.initials: A
authors.lastname: Abbout
authors.forename: Gabriel
authors.initials: G
authors.lastname: Lemarié
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Pichard