Pressure dependence of the optical absorption edge of Cd1-xMnxSe.

Abstract

The effect of pressure on the absorption edge of ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Mn}}_{\mathrm{x}}$Se with different compositions has been measured. A pinninglike behavior has been observed for the mixed crystal with x=0.45, that is, the pressure coefficient decreases from about 6\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}3}$ eV/kbar at low pressures to almost zero at pressures Pg10 kbar. The pinning is attributed to the effect of the intraionic transitions of ${\mathrm{Mn}}^{2+}$. Furthermore, the energy of the absorption edge becomes independent of the polarization of incident light for the same sample at pressures at which the absorption edge is pinned, which confirms the above interpretation. The relation between phase-transition pressure and composition in ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Mn}}_{\mathrm{x}}$Se is also presented.