Abstract
A parametrization of the Abell‐Tersoff potential for In, Ga, As, InAs, and GaAs is presented by using both experimental data and results from density-functional calculations as input. This parametrization is optimized for the description of structural and elastic properties of bulk In, Ga, As, InAs, and GaAs, as well as for the structure and energy of several reconstructed low-index GaAs and InAs surfaces. We demonstrate the transferability to GaAs and InAs high-index surfaces and compare the results to those obtained with previously published parametrizations. Furthermore, we demonstrate the applicability to epitaxial InAs/GaAs films by comparing the Poisson ratio and elastic energy for biaxial strain, as obtained numerically with our potential and analytically from continuum-elasticity theory. Limitations for the description of point defects and surface diffusion are pointed out. This parametrization enables us to perform atomically detailed studies of InAs/GaAs heterostructures. The formation energy of InAs quantum dots on GaAs001 obtained from our atomistic approach is in good agreement with previous results from a hybrid approach.
Highlights
Contemporary semiconductor technology utilizes structures in which the mobility of the electronic carriers is restricted in one, two, or all three dimensions of spacequantum wells, wires, and dots, respectively
A simulation technique that is accurate yet computationally not too expensive is sought for. Such a technique should yield accurate atomic positions and strain fields since these are required as input for electronic structure calculationsusing, e.g., effective mass, k · p theory, or tight-binding approachesto calculate the electronic properties of the heterostructures
We provide a parametrization of the Abell– Tersoff potential that is optimized for the description of InAs/GaAs nanostructures
Summary
Contemporary semiconductor technology utilizes structures in which the mobility of the electronic carriers is restricted in one, two, or all three dimensions of spacequantum wells, wires, and dots, respectively. It simultaneously captures both bulk and surface properties with high overall accuracy With this parametrization, it is possible to perform reliable atomistic relaxations of InAs/GaAs nanostructures for quantitative studies of the total energies with dependable contributions from strained bulk and surface reconstructions. Murdick et al. presented a GaAs parametrization of an improved bond-order functional that employs a penalty function to account for the electron counting rule for reconstructed surfaces This very promising approach yields a good qualitative description of surface energies and defect energies and is able to describe intermediate bonding situations that might occur during, e.g., dynamic simulations of changes in the surface reconstruction. The remainder of this paper is devoted to calculating the sizedependent formation energy of a representative QD and comparing the results to a previously employed hybrid approach that combined continuum-elasticity theory and DFT calculationsRefs. 16 and 17͒
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