Electric field gradients at Ta in Zr and Hf inter-metallic compounds

• Published in: Solid state communications Vol. 121; no. 9; pp. 525 - 529
• Main Authors: Terrazos, L.A, Petrilli, H.M, Marszalek, M, Saitovitch, H, Silva, P.R.J, Blaha, P, Schwarz, K
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 07-03-2002; Elsevier
• Subjects: A. Metals; Condensed matter: electronic structure, electrical, magnetic, and optical properties; D. Electronic band structure; E. NQR; Electric field gradients; Electron states; Exact sciences and technology; Level splitting and interactions; Nuclear states and interactions; Physics; Electric field gradients; 23.20.En; A. Metals; 71.20.Lp; 71.70.Jp; 71.15.Ap; 76.30.Da; D. Electronic band structure; 31.30.Gs; E. NQR; Band structure; Inorganic compounds; Intermetallic compounds; Coupling constants; Quadrupole interactions; Metals; Transition element compounds; Lattice relaxation; APW calculations; Metallic bonds; Silver; Perturbed angular correlation; Substitutional impurities; Hafnium; Impurity site; Aging; Ab initio calculations; Copper
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/S0038-1098(01)00515-4

Here we calculate the electric field gradient (EFG) at the nucleus of the substitutional Ta impurity site in Zr
2T and Hf
2T (T=Cu, Ag, Au, and Pd) C11
b inter-metallic compounds. We use the ab initio FP-LAPW method as embodied in the Wien97 code in a super-cell approach and include lattice relaxations around the impurity. Our results are compared with EFG values inferred from measurements of the quadrupole coupling constants at the
111Ta probe in these compounds performed with the time differential perturbed angular correlation (TDPAC) technique. We also performed EFG calculations for the pure inter-metallic compounds. Through the comparison of theoretical and experimental EFGs in these cases, we elucidate the role played by the Ta probe in the TDPAC measurements of Hf and Zr compounds. Our results show that, although the EFGs at the Hf site are very similar to the EFGs at the Ta impurity, there is no direct correlation between the Zr and Ta EFGs.