Spin Transport in (110) GaAs-Based Cavity Structures

The anisotropic spin dephasing of optically generated electrons in an undoped (110) GaAs quantum well inside a microcavity structure is investigated by means of spatially resolved photoluminescence experiments at a temperature of T=80 K. The dynamic type-II potential modulation induced by a surface acoustic wave (SAW) is used to transport electrons spatially separated from holes. Thus, the D’yakonov–Perel’ (DP) and the Bir–Aronov–Pikus spin dephasing mechanisms are suppressed, and electron spins can be transported over long distances of about 24 μm, which correspond to spin lifetimes of at least 8 ns. The spin vector can be rotated by an external in-plane magnetic field or by the effective in-plane field resulting from the structural inversion anisotropy induced by an intense SAW. This rotation generates an in-plane spin component that is subject to the DP spin dephasing mechanism. By means of Hanle effect measurements the lifetime of this in-plane spin component is found to be of 0.7 ns.