Pressure dependence of the natural birefringence in the II-IV-V-2 chalcopyrite CdGeP2

Abstract

Chalcopyrite semiconductors are birefringent as a result of their tetragonal crystal lattice structure. The dispersion of this birefringence contains contributions from the near-bandgap transitions and also from higher energy hand-to-hand transitions. We report the effect of pressure on the dispersion of the natural birefringence in CdGeP2. We found that pressure tends to decrease both contributions. The pressure effect on the near-bandgap contribution results mostly from an increase of the bandgap with pressure.