Optical injection of charge current in quantum wires: Oscillations induced by excitonic effects

Abstract

We investigate the charge current that is optically injected by interference between one- and two-photon excitation in the presence of excitonic effects. We consider a realistic V-shaped quantum wire excited slightly below the band gap by two simultaneous femtosecond laser pulses of frequency $2\ensuremath{\omega}$ and $\ensuremath{\omega}$ that interact, respectively, with the lowest ${B}_{1}$ and ${A}_{1}$ excitons. Using effective multiband Bloch equations for two-photon transitions, including the Coulomb interaction within the Hartree-Fock approximation, we show that, because of the different symmetry properties of the involved excitons, the generated charge current displays oscillations due to the quantum interference between the excitonic coherences.