Effective elastic stiffnesses of InAs under uniform strain

The effective elastic stiffnesses C-11, C-12 and C-44 of InAs and derived elastic constants are determined for states of uniform volumetric strain by atomistic simulation. The effective elastic stiffnesses C-11 and C-12 are found to increase significantly with strain whereas C-44 is found to be nearly independent of strain. Results for the bulk modulus are consistent with high-pressure experiments and nonlinear elasticity theories. The effective Young's modulus is found to be nearly independent of strain whereas the effective Poisson's ratio increases by about 40% over the range 0%-20% volumetric strain. The use of effective elastic stiffnesses within the isotropic approximation leads to a hydrostatic strain for an InAs quantum dot which is 16% smaller than the uncorrected value. It is concluded that continuum techniques for calculating quantum-dot-induced strain in the InAs/GaAs system should include strain-dependent InAs elastic stiffnesses for maximum accuracy. (C) 2002 American Institute of Physics.