Symmetry adapted impurity modes in as grown n-type GaP:X and GaSb:X (X = S, Se and Te)
A comprehensive average-t-matrix Green's function (ATM-GF) theory is used, in the framework of a realistic rigid-ion-model, to simulate the symmetry induced vibrational modes of different defect centers in GaP:X and GaSb:X (X = S, Se and Te) crystals. Explicit calculations are performed for isolated 32SP+ (34SP+) defects, nearest-neighbor 32SP+-CuGa2- (34SP+-CuGa2-) pairs in GaP, and next-nearest-neighbor complex 32SSb+-GaSb2-(34SSb+-GaSb2-) center in GaSb by using apposite perturbation (P↔) and Green's function (G↔o) matrix elements. For the isolated closest mass isoelectronic and charged (donor and acceptor) defects, the study has provided a convincing empirical relationship associating the increase or decrease of force constant change between impurity-host atoms to the increase or decrease of covalency of impurity-host bond. The rule has accurately predicted the observed isotopic shifts of local vibrational and/or gap modes of isolated impurities and offered modes for different “donor–acceptor” pairs of reduced symmetry. We feel that the ATM-GF method will play a significant role identifying the site selectivity of defects for estimating their mode frequencies in the technologically important semiconductor materials.
Computational Materials Science
Digital Object Identifier (DOI)
Talwar, D.N. (2022) Symmetry adapted impurity modes in as grown n-type GaP:X and GaSb:X (X = S, Se and Te). Computational Materials Science, 204, 111174. https://doi.org/10.1016/j.commatsci.2021.111174