APW+lo and TDPAC Study of the Electric-Field Gradients at the Cation Sites of the 44Ti(EC)44Sc-doped Semiconductor Sc2O3

E.L. MUÑOZ, D. RICHARD, T. BUTZ, L.A.ERRICO, AND M. RENTERÍA.

Århus

Workshop; International Workshop “Quantum Theory of Solids (QTS-5)”; 2009

University of Århus, Dinamarca

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US; mso-fareast-language:ES-AR;} pre {margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Courier New"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES-AR; mso-fareast-language:ES-AR;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US;} @page Section1 {size:841.9pt 595.3pt; mso-page-orientation:landscape; margin:3.0cm 70.9pt 3.0cm 70.9pt; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> We report on an ab initio study of the electric-field-gradient tensor (EFG) at both inequivalent Sc sites in the semiconductor Sc2O3. Calculations were performed with the Full-Potential Augmented-Plane Waves plus Local Orbitals (FP-APW+lo) method that allows us to treat the electronic structure and the atomic position refinements in a fully self-consistent way. Our results are compared with recent experimental data determined by Time-Differential gamma-gamma  Perturbed-Angular Correlation (TDPAC) spectroscopy using the first excited I=1 state of the 44Ti(EC)44Sc isotope. It is clear from our results that simple models such as the Point Charge Model can not even approximately describe the measured EFGs at cation sites in pure scandium sesquioxide.