Experimental verification of calculated lattice relaxations around impurities in CdTe
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We have measured the lattice distortion around As (acceptor) and Br (donor) in CdTe With fluorescence detected X-ray absorption spectroscopy. We Could experimentally verify the lattice relaxation with a bond length reduction of 8% around the As atom as inferred indirectly from ab initio calculations of the electric field gradient performed with the WIEN97 package in comparison with the measured value in a Perturbed Angular Correlation experiment as recently reported. We have complemented Our own calculations of relaxation with WIEN97 with calculations using the FH196md pseudo-potential program, which allows the use of larger super-cell sizes. Encouraged by the good agreement between experiment and model calculation for As in CdTe as well as similarly for the isovalent Se in CdTe, we extended Our investigation to Br in CdTe, where the electric field gradient has also been Measured, and Could not only verify the derived lattice expansion around Br with Our EXAFS analysis but additionally... observe fractions of Br in the A-center as well as in a DX-center configuration.
Keywords:calculations with DFT theories with LAPW and pseudo-potential methods / dopants in CdTe / fluorescence detected X-ray absorption / lattice relaxation / local structure
Source:Hyperfine Interactions, 2004, 158, 1-4, 353-359
- Joint Meeting of the 13th International Conference on Hyperfine Interactions/17th International Symposium on Nuclear Quadrupole Interactions (HFI/NQI 2004), Aug 22-27, 2004, Bonn, Germany