Dynamical CPA and Tight-Binding LMTO Approach to Correlated Electron System
Abstract
Dynamical Coherent-Potential Approximation (CPA) to correlated electrons has been extended to a system with realistic Hamiltonian which consists of the first-principles tight-binding Linear Muffintin Orbital (LMTO) bands and intraatomic Coulomb interactions. Thermodynamic potential and self-consistent equations for Green function are obtained on the basis of the functional integral method and the harmonic approximation which neglects the mode-mode couplings between the dynamical potentials with different frequency. Numerical calculations have been performed for Fe and Ni within the 2nd-order dynamical corrections to the static approximation. The band narrowing of the quasiparticle states and the 6 eV satellite are obtained for Ni at finite temperatures. The theory leads to the Curie-Weiss law for both Fe and Ni. Calculated effective Bohr magneton numbers are 3.0 for Fe and 1.2 for Ni, explaining the experimental data. But calculated Curie temperatures are 2020 K for Fe and 1260 K for Ni, being still overestimated by a factor of two as compared with the experimental ones. Dynamical effects on electronic and magnetic properties are discussed by comparing with those in the static approximations.
Keywords
Cite
@article{arxiv.0807.0847,
title = {Dynamical CPA and Tight-Binding LMTO Approach to Correlated Electron System},
author = {Y. Kakehashi and T. Shimabukuro and T Tamashiro and T. Nakamura},
journal= {arXiv preprint arXiv:0807.0847},
year = {2008}
}
Comments
To be published in J. Phys. Soc. Jpn. 77 No.9 (2008)