理论分析了两种阻尼条件下重掺杂GaAs中的等离子体激元-LO声子耦合模,证实在小阻尼条件下耦合模的拉曼谱分为两支,而在大阻尼条件下只有一个耦合模可以被观测到。推导得到了只出现一个耦合模所需的最小阻尼的解析表达式。测量了Mn组分从2.6%到9%的GaMnAs合金的拉曼光谱。利用等离子体激元-LO声子耦合模理论进行了谱形拟合,得到了所测的GaMnAs合金中的空穴浓度。
The coupled plasmon- LO phonon (CPLP) modes in heavily doped GaAs have been investigated theoretically for two damping conditions. It was demonstrated that there exist two branches of CPLP modes in the small damping condition. However, only one CPLP mode appears in the large damping condition. The analytic expression of the minimum damping constant for observation of one CPLP mode was deduced. The Raman spectra of GaMnAs alloy with Mn composition from 2.6 % to 9 % were measured and analyzed according to the theory of CPLP modes. The hole densities of the GaMnAs alloy were then determined.