Direct observation of depolarization shift of the intersubband resonance

Research paper by S Graf, H Sigg, K Kohler, W Bachtold

Indexed on: 04 Oct '00Published on: 04 Oct '00Published in: Physical review letters


We have studied the intersubband resonance of GaAs/AlGaAs multi-quantum-well systems by comparing photon drag and absorption spectra obtained by in-plane photocurrent and photoconduction measurements. The peak absorption at room temperature is found to be blueshifted from the photon drag resonance by as much as 33 cm(-1). We argue that this difference gives directly the depolarization shift, since the resonant photon drag current is driven by the Doppler effect, which is a k-vector dependent single particle process.