Quantum spin current induced through optical dipole transition process in semiconductors

Abstract

We propose a scheme to generate quantum spin current via linear optical process. By interacting a three-level system based on the spin states of charged particles (electrons or holes in semiconductor, etc) with the angular momentum states of an optical field, we show that the dynamics of charged particles equipped with different spin polarizations are governed by different (opposite) additional effective magnetic fields. In this way, a pure dissipationless quantum spin current can be generated. No spin-orbit interaction (e.g., Rashba or Dresselhaus term) is needed in this scheme. We also calculate the effect of nonmagnetic impurities on the created spin currents and show that the vertex correction of the spin hall conductivity in the ladder approximation is exactly zero. © World Scientific Publishing Company.