Electronic structure of Mott insulators. [Insulating gap, local moment, effective spin Hamiltonian]

Journal Article · Sat Jan 01 04:00:00 EST 1977 · Adv. Phys.; (United States)

DOI:https://doi.org/10.1080/00018737700101443· OSTI ID:6897364

Brandow, B H

Mott insulators are identified here with ordinary magnetic insulators. The insulating gap, local moment, and effective spin hamiltonian aspects are qualitatively explained by means of a novel set of solutions of the Hartree-Fock equations. The apparent conflict between Bloch's theorem and localized-electron phenomenology is thereby resolved in an elementary manner. This Hartree-Fock approach also sheds considerable light on the physical mechanisms responsible for the associated metal-insulator (Mott) and other related phase transitions, as observed in V/sub 2/O/sub 3/ and several other materials. With some generalizations and refinements, this theoretical picture is shown to also account semiquantitatively for a number of detailed properties of NiO and CoO, two of the most extensively studied Mott insulator materials. A wide variety of experimental data for NiO is surveyed in order to determine reasonable values for its effective Hubbard hamiltonian parameters, suitably generalized for the 3d electrons. The problems of formally deriving effective spin hamiltonians for macroscopic magnetic insulator systems are also carefully examined. The old nonorthogonality catastrophe is fully resolved by means of a degenerate (open-shell) analogue of the linked cluster perturbation expansion of Brueckner and Goldstone. Although many quantitative issues remain, these results indicate that there is now a reasonably adequate conceptual understanding of the Mott insulating state.

• Research Organization: Los Alamos Scientific Lab., NM
• OSTI ID: 6897364
• Journal Information: Adv. Phys.; (United States), Journal Name: Adv. Phys.; (United States) Vol. 26:5; ISSN ADPHA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ANGULAR MOMENTUM
BLOCH THEORY
CHALCOGENIDES
COBALT COMPOUNDS
COBALT OXIDES
ELECTRICAL EQUIPMENT
ELECTRICAL INSULATORS
ELECTRONIC STRUCTURE
EQUIPMENT
HAMILTONIANS
HARTREE-FOCK METHOD
MAGNETIC MOMENTS
MANGANESE COMPOUNDS
MANGANESE OXIDES
MATHEMATICAL OPERATORS
NICKEL COMPOUNDS
NICKEL OXIDES
NICKEL SULFIDES
OXIDES
OXYGEN COMPOUNDS
PARTICLE PROPERTIES
PERTURBATION THEORY
PHASE TRANSFORMATIONS
QUANTUM OPERATORS
SPIN
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
VANADIUM COMPOUNDS
VANADIUM OXIDES