We report g tensors of surface color centers, so-called F-s(+) centers, of MgO calculated with two density-functional approaches using accurately embedded cluster models. In line with recent UHV measurements on single-crystalline MgO film, we determined only small g-tensor anisotropies and negative shifts Delta g equivalent to g-g(e) for all F-s(+) sites considered, namely, (001)-terrace, step, edge, and corner sites. The g values are very sensitive to the local structure of the defect: relaxation reverses the sign of Delta g. However, accounting for the spin-orbit interaction either self-consistently or perturbatively yields very similar results. In addition to the values of the tensor components, their direction with respect to the surface was determined. In contrast to edges, significant deviations from ideal C-2v symmetry were found for F-s(+) centers at steps. Recent data on single-crystalline thin films are reevaluated in the light of these results
DI VALENTIN, C., Neyman, K., Risse, T., Sterrer, M., Fischbach, E., Freund, H., et al. (2006). Density-functional model cluster studies of EPR g tensors of F-s(+) centers on the surface of MgO. THE JOURNAL OF CHEMICAL PHYSICS, 124(4), 044708-1-044708-7 [10.1063/1.2161190].
Density-functional model cluster studies of EPR g tensors of F-s(+) centers on the surface of MgO
DI VALENTIN, CRISTIANA;PACCHIONI, GIANFRANCO;
2006
Abstract
We report g tensors of surface color centers, so-called F-s(+) centers, of MgO calculated with two density-functional approaches using accurately embedded cluster models. In line with recent UHV measurements on single-crystalline MgO film, we determined only small g-tensor anisotropies and negative shifts Delta g equivalent to g-g(e) for all F-s(+) sites considered, namely, (001)-terrace, step, edge, and corner sites. The g values are very sensitive to the local structure of the defect: relaxation reverses the sign of Delta g. However, accounting for the spin-orbit interaction either self-consistently or perturbatively yields very similar results. In addition to the values of the tensor components, their direction with respect to the surface was determined. In contrast to edges, significant deviations from ideal C-2v symmetry were found for F-s(+) centers at steps. Recent data on single-crystalline thin films are reevaluated in the light of these resultsI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.