Density of states in narrow energy bands

✍ Scribed by O. Goscinski

• Publisher: Elsevier Science
• Year: 1971
• Tongue: English
• Weight: 203 KB
• Volume: 9
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(71)80223-3

✦ Synopsis

It was pointed out by

Bari and Kaplan [l]

that, contrary to expectations, the single-particle Green function decoupling procedure due to Hubbard [2], when applied to the one band short-range interaction mode!. [2], does not reduce to the Hartree-Fock approximation for arbitrarily small, but finite, interaction energy I. By use of an expansion in powers of Z/ek the Hartree-Fock approximation follows for all f?k except in the neighborhood of ek = 0. (The zero of energy was chosen at To = EC?&) This excluded region, it was remarked, often has little effect on the physical properties but it may modify magnetic properties in an essential way [l]: the validity of the I-IF or RPA limits of HubSard's decoupiing [3,4] in connection with antiferromagnetic instabilities was questioned in this vein 111.