流体静压下AlAs合金化的GaAs中Cr2+(3d4)杂质态的理论研究

本文将一个自旋极化的紧束缚格林函数方法发展到用于流体静压和合金下GaAs:Cr²⁺(3d⁴)杂质态的研究。文中给出了GaAs:Cr²⁺系统⁵E激发态和⁵T₂基态受主能级随压力和AlAs合金成份的变化趋势。理论证明了在一定的压力和Al成份下,⁵E激发态将从导带底进入带隙,原在通常条件下观察不到的⁵E→⁵T_关键词：

INVESTIGATION OF THE Cr2+(3d4) IN GaAs UNDER HYDROSTATIC PRESSURE AND AlAs ALLOYING

A spin-polarized version of the tight-binding Green's function scheme is developed for GaAs:Cr²⁺(3d⁴) system, which is under hydrostatic pressure and is alloyed with AlAs in different concentration. Results on the variation trends of ⁵E excited and ⁵T₂ ground acceptor levels of GaAs:Cr²⁺ with different pressures and aluminum concentrations are reported. The theory shows that under certain pressure and Al concentration the ⁵E state will shift into the band gap from the bottom of conduction band. The ⁵E→⁵T₂ luminescence which can not be observed in normal condition will appear in such case. Good overall agreement between theory and experiment is found. The theory also predicts that the similar luminescence process-would occur when GaAs is alloyed with Gap in certain concentration, but this still waits for experimental verification.