Electronic structure of stoichiometric and off-stoichiometric TaC/sub x/

Journal Article · Tue Nov 15 04:00:00 EST 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.38.9538· OSTI ID:7015587

Schadler, G H; Boring, A M; Weinberger, P; Gonis, A

We have determined the electronic structure of stoichiometric and substoichiometric TaC by means of the relativistic Korringa-Kohn-Rostoker Green's-function method. The introduction of vacancies was treated within the coherent-potential approximation. We find that the main difference between the ordered and disordered compound is a charge transfer from the nonmetal to the metal atom. Additional vacancy states (-3.0 eV below the Fermi energy) play a minor role. We calculate x-ray photoemission spectroscopy (XPS) intensities for both stoichiometric and substoichiometric cases and find (unlike previous calculations) excellent agreement with the XPS data. We also compare our results with the measured linear specific-heat coefficient and find that the sharp drop seen in this quantity with increasing vacancy concentration cannot be explained by our results.

• Research Organization: Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 7015587
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 38:14; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
CARBIDES
CARBON COMPOUNDS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
ELECTRONIC STRUCTURE
ENERGY RANGE
FUNCTIONS
GREEN FUNCTION
IONIZING RADIATIONS
PHOTOELECTRON SPECTROSCOPY
PHYSICAL PROPERTIES
POINT DEFECTS
RADIATIONS
REFRACTORY METAL COMPOUNDS
RELATIVISTIC RANGE
SPECIFIC HEAT
SPECTROSCOPY
STOICHIOMETRY
TANTALUM CARBIDES
TANTALUM COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
VACANCIES
X RADIATION