Role of nonequilibrium dynamical screening in carrier thermalization

Article

关键词: EFFECTIVE BLOCH EQUATIONS;    GAAS QUANTUM-WELLS;    PHOTOEXCITED CARRIERS;    ELECTRON-SCATTERING;    LOW-DENSITY;    BULK GAAS;    SEMICONDUCTORS;    RELAXATION;    LUMINESCENCE;    GENERATION;   

DOI  :  10.1103/PhysRevB.55.1517

来源: SCIE

【 摘 要 】

We investigate the role played by nonequilibrium dynamical screening in the thermalization of carriers in a simplified two-component two-band model of a typical semiconductor like GaAs. The main feature of our approach is the theoretically sound treatment of collisions. We abandon Fermi's golden rule in favor of the nonequilibrium field-theoretic approach. However, we do not employ the Kadanoff and Baym ansatz or its generalizations. Explicit formulas are derived for the nonequilibrium screened Coloumb interaction, and the manner in which screening builds up is explained. We also compute the polarization dephasing rate as a function of the excited carrier density. At densities less than 8 x 10(13) cm(-3), it is found that the dephasing rate due to carrier-carrier scattering is proportional to the carrier density, and for densities in the range 1x10(15)-10(16) cm(-3) the dephasing rate scales sublinearly with the density, which enables a comparison with experiment. The dephasing of excitonic quantum beats as a result of carrier-carrier scattering is also brought out.

【 授权许可】

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