It is considered here the problem of the microscopic theory of the indirect exciton spin relaxation in III-V semiconductor quantum wells. The direct exciton spin relaxation is that between the optical active states driven by the electron-hole exchange interaction. In the indirect case the heavy-hole exciton spin is flipped after sequential spin flips of the single particles. We show that this relaxation channel is driven by the k e3 spin-orbit splitting in the conduction band due to inversion asymmetry. Adding such interaction to the exciton Hamiltonian we obtain an effective exciton spin Hamiltonian corresponding to a pseudo spin 1/2 in an effective Koarr-dependent magnetic field, which changes randomly with elastic scattering of the center-of-mass momentum Koarr. It describes the exciton-bound electron spin dynamics, and allows the calculation of the relaxation rate (W e), that limits the exciton spin relaxation rate in the indirect channel. We obtain W e as a function of the material and structure parameters. The estimated values are shown to be in good accord with the available experimental data

Indirect exciton spin relaxation in semiconductor quantum wells

LA ROCCA, Giuseppe Carlo
1997

Abstract

It is considered here the problem of the microscopic theory of the indirect exciton spin relaxation in III-V semiconductor quantum wells. The direct exciton spin relaxation is that between the optical active states driven by the electron-hole exchange interaction. In the indirect case the heavy-hole exciton spin is flipped after sequential spin flips of the single particles. We show that this relaxation channel is driven by the k e3 spin-orbit splitting in the conduction band due to inversion asymmetry. Adding such interaction to the exciton Hamiltonian we obtain an effective exciton spin Hamiltonian corresponding to a pseudo spin 1/2 in an effective Koarr-dependent magnetic field, which changes randomly with elastic scattering of the center-of-mass momentum Koarr. It describes the exciton-bound electron spin dynamics, and allows the calculation of the relaxation rate (W e), that limits the exciton spin relaxation rate in the indirect channel. We obtain W e as a function of the material and structure parameters. The estimated values are shown to be in good accord with the available experimental data
1997
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/2213
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