2008/06/02 by R. Eder
Chemistry · Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Chemistry #Cluster (spacecraft) #Computer science #Condensed matter physics #Crossover #High-pressure geophysics and materials #Lattice (music) #Magnetic and transport properties of perovskites and related materials #Non-blocking I/O #Physics #Physics of Superconductivity and Magnetism #Spectral function #Statistical physics #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.78.115111
14 pages, 17 figures
arxiv created 2008/06/02 · openalex publication_date 2008/09/15 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The variational cluster approximation proposed by Potthoff is applied to the calculation of the single-particle spectral function of the transition-metal oxides MnO, CoO, and NiO. Trial self-energies and the numerical value of the Luttinger-Ward functional are obtained by exact diagonalization of a TMO6 cluster. The single-particle parameters of this cluster serve as variational parameters to construct a stationary point of the grand potential of the lattice system. The stationary point is found by a crossover procedure, which allows to go continuously from an array of disconnected clusters to the lattice system. The self-energy is found to contain irrelevant degrees of freedom, which have marginal impact on the grand potential and need to be excluded to obtain meaningful results. The obtained spectral functions are in good agreement with experimental data.