First principle study of the elastic properties of InGaAs with different doping concentrations of indium

Abstract

The electronic structure and elastic properties of the InGaAs crystal with different doping concentrations of indium are studied by the plane-wave pseudopotential method based on density functional theory with Cambridge Serial Total Energy Package programme. The density of states and the elastic constants of the InGaAs crystal with different doping concentrations of indium are obtained. The elastic modulus is also calculated from the theoretical elastic constants by Voigt–Reuss–Hill averaging scheme. The band gaps of the InGaAs crystal decrease monotonically with increasing indium concentration. Similarly, the elastic constants of the InGaAs crystal with the symmetry of cubic crystal system decrease monotonically with increasing indium concentration. With increasing indium concentration, the brittleness of the InGaAs crystal decreases and the ductility of the InGaAs crystal increases monotonically, resulting in the tangential deformation of the supercells which is more prone to occur. The values of the elastic constants obtained will be helpful in analysing the elastic properties of InGaAs/GaAs semiconductor saturable absorber mirror and in guiding the application of InGaAs/GaAs as a saturable absorber in passively Q-switched laser.