Mixed Basis Method with Overlapping Atomic Orbitals

Abstract

The LCAO-PW mixed basis method is considered in its most general formulation, i.e. with due account for overlapping AO's as well. By approximating atomic wave functions and potentials with Gaussian-type functions analytical expressions are derived for all elements of the Hamiltonian and nofi -orthogonality matrices. As an example, a silicon crystal is considered.

Magnetic properties of Fe–Ni invar calculated in the dynamic non-local approximation of the spin fluctuation theory

“…x , V 2 z , V z and µ. This system is only slightly more complicated than the one obtained in the static local approximation (SLA) [30]. In fact, taking account of dynamics and spatial correlations leads to modification of the formula for the spin fluctuations V 2 α only.…”

“…where ν(ε) is the non-magnetic DOS (per atom, band, and spin). From equation ( 12), for the fluctuation contribution σ , in the second order of field fluctuations V we obtain the formula [30]…”

Numerical calculation of local magnetic characteristics of Fe, Co and Ni at finite temperatures

“…Secondly, and above all, our values for the constant u depend on the degree of smoothing of the DOS. So, in our paper [26] the DOS for Fe was smoothed with Table 1. Our results for the effective constant of the electron-electron interaction u of Fe, Co and Ni, compared to the corresponding results for the exchange-correlation (effective Stoner) parameter I obtained in LSDA (all values in units of eV).…”

Temperature dependence of nuclear spin-relaxation rates for Fe, Co and Ni

“…A method for self-consistent calculation of magnetic properties of ferromagnetic metals at finite temperatures, based on the usage of real band structure and spin fluctuations, was developed in detail in [8,9]. Here we give only the basic ideas of the method and present the formulae necessary for calculation of relaxation rates, or more exactly, self-consistent calculation of local susceptibilities.…”

“…In this case the relaxation rate is just the Fourier transform of the electron spin correlation function at the nuclear magnetic resonance (NMR) frequency, which by the fluctuation-dissipation theorem can be expressed in terms of the magnetic susceptibility [7]. The relation between the nuclear spin-relaxation rate and magnetic susceptibility permits one to calculate the relaxation rates for ferromagnetic metals at finite temperatures using the spin-fluctuation theory (SFT) developed by the author and a co-author in [8,9] and successfully applied to Fe, Co and Ni in [10].…”