Open AccessMany‐body approach to crystal‐field theory
Author(s) -
Brouder Ch.
Publication year - 2005
Publication title -
physica status solidi (c)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 46
eISSN - 1610-1642
pISSN - 1610-1634
DOI - 10.1002/pssc.200460211
Subject(s) - hamiltonian (control theory) , density matrix , physics , matrix (chemical analysis) , many body theory , crystal (programming language) , field (mathematics) , statistical physics , function (biology) , quantum mechanics , mathematics , materials science , computer science , pure mathematics , mathematical optimization , evolutionary biology , composite material , quantum , biology , programming language
Abstract A self‐consistent many‐body approach is proposed to build a first‐principles crystal field theory, where crystal field parameters are calculated ab initio. We use nonequilibrium many‐body theory to write the energy of the interacting system as a function of the density matrix of the noninteracting system. A variation of the energy with respect to the density matrix gives an effective Hamiltonian matrix where all parameters are determined explicitly and self‐consistently. This effective Hamiltonian is diagonalized to determine the density matrix providing the lowest energy of the interacting system.