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 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.
@article{arxiv.1011.4559,
title = {Thermal Enhancement of Interference Effects in Quantum Point Contacts},
author = {Adel Abbout and Gabriel Lemarié and Jean-Louis Pichard},
journal= {arXiv preprint arXiv:1011.4559},
year = {2012}
}