STRAIN EFFECTS ON THE MICROSCOPIC STRUCTURE OF AN INXGA1-XAS EPILAYERIN INXGA1-XAS GAAS HETEROSTRUCTURES - A THEORETICAL-STUDY/

Several strained structures of two ideal InxGa1-xAs compounds have bee n investigated by performing ab initio total-energy and atomic-force c alculations in order to give a microscopic interpretation of extended x-ray-absorption fine-structure results on strained InxGa1-xAs/GaAs he terostructures. The achieved results show that the strain is accomodat ed by significant bond-angle distortions and small In-As bond contract ions. A striking, stretched Ga-As distance (close to the In-As one) ob served in the strained heterostructures should not be related therefor e to the strain accomodation occurring in the InxGa1-xAs epilayer. Ani sotropic strain effects are found, which lead to two different next-ne arest-neighbor distances for atomic pairs on and out of the planes par allel to the InxGa1-xAs/GaAs interfaces.