Premium
Functional integral approach for a doubly degenerate Hubbard model
Author(s) -
Richter A.,
Röpke G.,
Goedsche F.
Publication year - 1979
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220940214
Subject(s) - hubbard model , degenerate energy levels , ferromagnetism , condensed matter physics , electron , physics , phase diagram , magnetic moment , atom (system on chip) , electronic correlation , quantum mechanics , phase (matter) , superconductivity , computer science , embedded system
The method of the functional integral is applied to a doubly degenerate Hubbard model with arbitrarily filled bands. The relation between the number of electrons per atom n , and the chemical potential μ, the local moments, and the static susceptibilities corresponding to the magnetic, orbital, and charge‐ordered states are studied. At zero temperature a phase diagram is obtained in dependence on the electron concentration n , correlation energy U , intra‐atomic exchange energy I , and half bandwidth Δ. The exchange energy is important for the stability of the ferromagnetic state. Additionally to magnetic long‐range ordering an ordering of the orbital states within the ferromagnetic region is possible.