Charge distribution and electric-field gradients inYBa2Cu3

The Energy Dispersion of the Chain Band in YBa2Cu3O6+x and Its Effect on the Cu(2) NQR Frequency

“…On the other hand the number of | x2 -y2> holes, which are affected most by correlation, is con siderably lower in [12] than our value of about 0.8. The comparison of [12,13] with our results shows that, refering to LDA, additional inclusion of manyparticle correlation hould deplete the number of holes with 13 z2 -r2> symmetry (fills these states with elec trons) and increases the number of |x2-y2} holes (empties these electronic states). This trend is also sup ported by comparing the results of [12] with experi ment.…”

“…Schwarz et al find rather good agreement of the theoretical EFG's with the experiment at nearly all sites, except of Cu(2). They state that the number of holes in the 13z2 -r2> orbital was overestimated by their calculations [12]. This is probably due to LDA, because further inclusion of correlation effects would lead to narrower bands.…”

“…1 b. The EFG's in YBa2Cu30 6+ y were calculated by Schwarz et al using their fullpotential linear augmented-plane-wave model within the local-density approximation (LDA) [12,13]. Here we use the hole picture for a discussion of their results in connection with ours.…”

Density functional theory investigation of3dtransition metal NMR shielding tensors in diamagnetic systems using the gauge-including projector augmented-wave method

“…[3,43] The efficiency of the EFG calculations has been demonstrated for a large series of nuclei. [44][45][46][47] Nevertheless, when considering a second-order magnetic response as the shielding tensor, intricacies appears. It was demonstrated that the PAW approach does not preserve the translational invariance of eigenvectors in the presence of a uniform magnetic field.…”

Ab InitioStudy of Acceptor-Donor Complexes in Silicon and Germanium

“…For instance, the main axis of the EFG is found to point along the [111] direction (h 0), which strongly suggests a nearest neighbor (nn) pair configuration. However, for a fundamental understanding of the complexes electronic structure calculations are needed [3], which can be performed with good precision by density-functional methods [6,7]. The use of pseudopotential methods, which usually give excellent results in semiconductor physics, is not suitable in this case since the EFG is determined by the p charge density in the inner core region [6], so that up to now no theoretical treatment of these fundamental acceptor-donor complexes in Si and Ge exists.…”