Spin Conserving Tunneling in Asymmetric Double Quantum Well Structures

We present cw studies of exciton tunneling performed on CdTe-based asymmetric double quantum well structure. With the use of a semimagnetic semiconductor QW in magnetic field, we are able to align the carriers' spins before the tunneling. Using a polarization resolved photoluminescence excitation technique we obtain information on the efficiency of the transfer as well as its polarization memory. We record a transfer of spin polarization between quantum wells accounting for a 10% degree of polarization of photoluminescence.