TY  - JOUR
AU  - Höhler, H.
AU  - Atodiresei, N.
AU  - Schroeder, K.
AU  - Zeller, R.
AU  - Dederichs, P. H.
TI  - Cd-vacancy and Cd-interstitial complexes in Si and Ge
JO  - Physical review / B
VL  - 70
IS  - 15
SN  - 1098-0121
CY  - College Park, Md.
PB  - APS
M1  - PreJuSER-40600
SP  - 155313
PY  - 2004
N1  - Record converted from VDB: 12.11.2012
AB  - The electrical-field gradient (EFG), measured, e.g., in perturbed angular correlation experiments, gives particularly useful information about the interaction of probe atoms like In-111/Cd-111 with other defects. The interpretation of the EFG is, however, a difficult task. This paper aims at understanding the interaction of Cd impurities with vacancies and interstitials in Si and Ge, which represents a controversial issue. We apply two complementary ab initio methods in the framework of density-functional theory, (i) the all electron Korringa-Kohn-Rostoker Green function method and (ii) the pseudopotential-plane-wave method, to search for the correct local geometry. Surprisingly we find that both in Si and Ge the substitutional Cd-vacancy complex is unstable and relaxes to a split-vacancy complex with the Cd on the bond-center site. This complex has a very small EFG, allowing a unique assignment of the small measured EFGs of 54 MHz in Ge and 28 MHz in Si. Also, for the Cd-self-interstitial complex we obtain a highly symmetrical split configuration with large EFG's, being in reasonable agreement with experiments.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000224855900055
DO  - DOI:10.1103/PhysRevB.70.155313
UR  - https://juser.fz-juelich.de/record/40600
ER  -