Electron-phonon interactions and the phonon anomaly in [beta]-phase NiTi

Journal Article · Thu Jul 15 04:00:00 EDT 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.2031· OSTI ID:6276197

Zhao, G L; Harmon, B N ^[1]

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1. Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50010 (United States)

The electronic structure of [beta]-phase NiTi has been calculated using a first-principles linear-combination-of-atomic-orbitals method. The resulting band structure was fitted with a nonorthogonal tight-binding Hamiltonian from which electron-phonon matrix elements were evaluated. The soft phonon near [ital Q][sub 0]=(2/3, 2) / (3 ,0)[pi]/[ital a], which is responsible for the premartensitic phase transition in [beta]-phase NiTi, is found to arise from the strong electron-phonon coupling of nested electronic states on the Fermi surface. Thermal vibrations and changes in electronic occupation cause a smearing of the nested features, which in turn cause a hardening of the phonon anomaly.

• OSTI ID: 6276197
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 48:4; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

665430* -- Other Topics in Quantum Fluids & Solids-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOY SYSTEMS
ALLOYS
BAND THEORY
BINARY ALLOY SYSTEMS
COUPLING
ELECTRON-PHONON COUPLING
ELECTRONIC STRUCTURE
ENERGY LEVELS
FERMI LEVEL
NICKEL ALLOYS
PHASE TRANSFORMATIONS
TITANIUM ALLOYS