BGU Physics Department
Colloquium, Nov. 28th, 2013
Scanning Gate Microscopy and Quantum Point Contacts
Jean-Louis Pichard, CEA Saclay, France
The conductance of the electron interferometer formed in a two dimensional electron gas between a quantum contact and the depletion region induced by the charged tip of a scanning gate microscope exhibits very unusual interference behaviors. This can be seen when one studies the interferometer conductance as a function of the position of the tip, of the opening of the contact and of the temperature.
Using a solvable model where the contact exhibits a simple spin-degenerate Breit-Wigner resonance, I shall explain the enhancement of the interference fringes induced by increasing the temperature  and the interference rings occurring in addition to fringes space by half the Fermi wavelength when the resonance is split by a Zeeman Field .
The observation of these two phenomena using either a quantum point contact or a Kondo dot above its Kondo temperature for the contact region will be eventually discussed.
 “Thermal Enhancement of Interference Effects in Quantum point Contacts”, Adel Abbout, Gabriel Lemarié and Jean-Louis Pichard, Phys. Rev. Lett. 106, 156810 (2011).
 “Scanning Gate Microscopy of Kondo Dots: Fabry-Pérot Interferences and Thermally Induced Rings”, Andrii Kleshchonok, Geneviève Fleury and Jean-Louis Pichard, arXiv:1305.0106 (2013).