First-principles calculations of 002 structure factors for electron scattering in strained In_xGa_1−xAs

Abstract

We report on computation of 002 structure factors for electron scattering in strained and unstrained In_xGa_1−xAs alloys (x=0 to 1) by the linearised augmented plane-wave+local orbitals (LAPW+lo) method. The calculations of strained InxGa1-xAs were performed according to the strain state in specimens with large, small, and intermediate thickness in the electron beam direction. Additionally, the effect of static atomic displacements is taken into account. The calculated 002 structure factor vanishes at an In concentration of 16.4 %. This value is in good agreement with previously reported experimental measurements. Our results are a significant improvement with respect to the isolated atom approximation which predicts a value of 22.5 %.