Anharmonicity-induced multiphonon processes in high-temperature superconductors

Journal Article · Thu Aug 01 04:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.44.2853· OSTI ID:5307654

Bussmann-Holder, A ^[1]; Bishop, A R ^[2]

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1. Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-7000 Stuttgart 80 (Germany) Universitaet Bayreuth, D-8580 Bayreuth (Germany)
2. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico (USA)

Electron--two-phonon interactions are considered on the basis of an extended BCS-type Hamiltonian. An equation for the superconducting transition temperature {ital T}{sub {ital c}} and the energy gap 2{Delta}{sub 0} is derived in the weak-coupling limit. Instead of a Debye frequency a reduced optic-acoustic mode frequency, together with a coupled effective electron-phonon interaction, determines the magnitude of {ital T}{sub {ital c}}. This leads to a distinctly different isotope effect from BCS, which is compared with data on La{sub 2{minus}{ital x}}Sr{sub {ital x}}CuO{sub 4}. The energy gap is predicted to be anisotropic and 2{Delta}{sub 0}/{ital kT}{sub {ital c}} to be compound dependent.

• OSTI ID: 5307654
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 44:6; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

656100* -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BCS THEORY
COUPLING
ELECTRON-PHONON COUPLING
ENERGY GAP
HAMILTONIANS
HIGH-TC SUPERCONDUCTORS
MATHEMATICAL OPERATORS
PHYSICAL PROPERTIES
QUANTUM OPERATORS
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE