Magnetic-field antisymmetry of photovoltaic voltage in evanescent microwave fields as seen in a semiconductor Hall bar
Résumé
A two-dimensional electron system without spatial inversion symmetry develops a sample specific dc voltage when exposed to a microwave radiation at low temperature. We investigate this photovoltaic (PV) effect in the case where spatial symmetry is broken by an evanescent high-frequency potential. We measure the induced PV voltage in a GaAs/ Ga1-x Alx As Hall bar at magnetic fields in the tesla range. We find that in this regime the induced PV voltage is antisymmetric with magnetic field and exhibits regular Shubnikov-de Haas-type oscillations. Our experimental results can be understood from a simple model, which describes the effect of stationary orbital currents caused by microwave driving.