Optical Absorption of Zn1−xMnxSiAs2 Single Crystals : Variation of the Energy Gap with Composition and Temperature

Abstract

We have investigated the Mn composition x and the temperature (12 K ≤ T ≤ 300 K) dependences of the energy gap of Zn 1-xMn xSiAs 2 crystals. Single crystals were grown by using the vertical Bridgman method for a series of Mn compositions x. The variation of the enery gap, E g, with temperature follows the Varshni's relation for all compositions. The energy gap decreased up to x ̃ 0.04. Thereafter, it increased with x. The energy gap bowing effect is related to the sp-d exchange interaction between the 3d electrons of magnetic Mn ions and the band electrons and to magnetic and chemical disorder.