Multiphonon Structure of Optical Transitions to Impurity Resonance States. The Influence of Anharmonicity

Abstract

Expressions are derived for the absorption coefficient of substitutional impurities taking into account resonant impurity states and anharmonicity of lattice vibrations. I n both the cases the lineshape of the absorption band is modified due to broadening effects. It can be shown that the contribution due to anharmonicity is not only remarkable, but dominates under certain conditions, for example, in the case of strong electron-phonon interaction.PaCCMaTpeHO lTOrJIO4eHIIe CBBTB, 06yCJIOBeHHee IIpIIMeCRMII IIpII HaJIMYHII pe30HaHCHbIX COCTORHIIfi II aHrapMOHH3Ma PeIIIeTO~HbIX ~o~1 e 6 a~~t i .nOJIOCa IIOrJIOlQeHHR II3MeHReTCFl BCJIenCTBHe 3aTYXaHIIEI, B03HIIHaIolQee IIpH HaJlIIYIIM yHa3aHHbIX B3aIIMOAeaCTBH8. nOHa3aH0, 9 T O BHJIElA aHrapMOHII3Ma He TOJIbHO 3aMeTH0, HO II MOmeT AOMMHHPOBaTb, OcO6eHHO B CJIyYae CHJIbHOrO WIeHTpOH-@OHOHHOrO B3aIIMOAetiCTBMR.