Electric field gradient calculations forLixTiS2and comparison withLi

Abstract

The elements of the electric field gradient tensor at Li position in the intercalation compound Li x TiS 2 (with x = 0.25, 0.33, 0.67, and 1.0) were calculated with first-principles methods and periodic supercell models. The theoretical results obtained with density functional and Hartree-Fock hybrid methods were compared with experimental field gradients extracted from 7 Li NMR spectra from the literature and from our measurements presented here. The dependence of calculated field gradients on the basis set and the explicit form of the exchange-correlation density functional was investigated. In agreement with earlier studies a pronounced effect of polarization functions at the Li site was observed. After optimization of internal degrees of freedom in LiTiS 2 all methods under consideration give quadrupole coupling constants in close agreement with experiment. For x Ͻ 1 the calculated quadrupole coupling constants were found to depend more sensitively on the method which was attributed to differences in the description of spin localization. The calculations allow one to distinguish between Li atoms placed at octahedral and tetrahedral interstitial sites of the host lattice TiS 2 .

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.…”

First-Principles Modeling of SrTiO3Based Oxides for Thermoelectric Applications

“…The electronic structure calculations have been performed using the linear combination of atomic orbitals method as implemented in CRYSTAL first-principles code. [73] We used localized Gaussian-type basis sets including polarization orbitals and considered all the electrons for Ti [74], O [75], V [78], K and Nb [76], F and Co [77]. The Hartree-Fock pseudopotential for Sr [75], and the Stuttgart energy-consistent pseudopotential for La [79] were used.…”

Tunable conductivity threshold at polar oxide interfaces

“…Calculations were performed using the linear-combination of atomic orbitals method implemented in the CRYSTAL code 35 . We used localized Gaussian-type basis sets including polarization orbitals and considered all the electrons for Ti 36 , O 37 and Al 38 . For Sr, we used a HartreeFock pseudopotential 37 .…”