Jeudi 07 mars 2013 à 10h15
Salle 234, Ecole de Physique

Equilibration of quantum Hall edge states by an Ohmic contact

Artur Slobodeniuk, Université de Genève, Département de Physique Théorique

Ohmic contacts are crucial elements of electron optics that have not received a clear theoretical description yet. We propose a model of an Ohmic contact as a piece of metal of the finite capacitance $C$ attached to a quantum Hall edge. It is shown that charged quantum Hall edge states may have week coupling to neutral excitations in an Ohmic contact. Consequently, despite being a reservoir of neutral excitations, an Ohmic contact is not able to efficiently equilibrate edge states if its temperature is smaller than $hbarOmega_c$, where $Omega_c$ is the inverse RC time of the contact. This energy scale for a floating contact may become as large as the single-electron charging energy $e^2/C$.