Negative electron-electron drag between narrow quantum Hall channels

Abstract

Momentum transfer due to Coulomb interaction between two parallel, two-dimensional, narrow, and spatially separated layers, when a current Idrive is driven through one layer, is studied in the presence of a perpendicular magnetic field B. The current induced in the drag layer Idrag is evaluated self-consistently with Idrive as a parameter. Idrag can be positive or negative depending on the value of the filling factor N of the highest occupied bulk Landau level (LL). For a fully occupied LL, Idrag is negative, (i.e., it flows opposite to Idrive), whereas it is positive for a half-filled LL. When the circuit is opened in the drag layer, a voltage Vdrag develops in it; it is negative for a half-filled LL and positive for a fully occupied LL. This positive Vdrag expressing a negative Coulomb drag, results from energetically favored near-edge inter-LL transitions that occur when the highest occupied bulk LL and the LL just above it become degenerate