Excitonic polaritons of zinc diarsenide single crystals

Abstract

Excitonic polaritons of ZnAs2 single crystals had been investigated. Parameters of singlet excitons with Г2¯(z) symmetry and orthoexcitons 2Г1¯(y)+Г2¯(x) had been determined. Spectral dependencies of ordinary and extraordinary dispersion of refractive index had been calculated using interferential reflection and transmittance spectra. It was shown, that A excitonic series were due to hole (V1) and electron (C1) bands. The values of effective masses of electrons (mc*=0.10m0) and holes (mv1*=0.89m0) had been estimated. It was revealed that the hole mass mv1* changes from 1.03m0 to 0.55m0 at temperature increasing from 10K up to 230K and that the electron mass mc* does not depend on temperature. The integral absorption A (eVcm−1) of the states n=1, 2 and 3 of Г2¯(z) excitons depends on the An≈n−3 equality, which it is characteristic for S-type excitonic functions. Temperature dependences of the integral absorption of ground states for Г2¯(z) and Г2¯(х) excitons differ. The ground states of B and C excitons formed by V3 – C1 and V4 – C1 bands and its parameters had been determined.