de Haas--van Alphen studies of the organic superconductors. alpha. -(ET) sub 2 (NH sub 4 )Hg(SCN) sub 4 and. kappa. -(ET) sub 2 Cu(NCS) sub 2 (with ET = bis(ethelenedithio)-tetrathiafulvalene)
- Materials Science and Chemistry Divisions, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
We report measurements of the de Haas--van Alphen (dHvA) effect in the organic superconductors {alpha}-(ET){sub 2}(NH{sub 4})Hg(SCN){sub 4} and {kappa}-(ET){sub 2}Cu(NCS){sub 2} in fields up to 15 T and temperatures down to 0.45 K. In both compounds, the perfect 1/cos{theta} behavior of the dHvA frequency for angles {theta} of the applied field up to 70{degree} from the normal to the conducting planes shows the strong two-dimensionality of the Fermi surface (FS). The angle-dependent magnetic-breakdown orbit found in {kappa}-(ET){sub 2}Cu(NCS){sub 2} hints at a small warping of the FS. The unusual angular dependence of the dHvA amplitude with up to 4 spin splitting zeros is quantitatively explainable by a 1/cos{theta} dependence of the bare band cyclotron-resonance effective mass. This distinctive behavior allows the separation of the mass enhancement due to electron-phonon coupling from the measured cyclotron-resonance effective mass and the estimation of the superconducting transition temperatures with the standard BCS formula, which are in qualitative agreement with the observed values.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 7272162
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 45:6; ISSN PRBMD; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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de Haas-van Alphen studies and Fermi surface properties of organic superconductors (ET)[sub 2]X
de Haas--van Alphen and Fermi surface studies of organic superconductors (ET) sub 2 X
Related Subjects
360606* -- Other Materials-- Physical Properties-- (1992-)
360607 -- Other Materials-- Superconducting Properties-- (1992-)
BCS THEORY
COUPLING
DE HAAS-VAN ALPHEN EFFECT
EFFECTIVE MASS
ELECTRON-PHONON COUPLING
MASS
ORGANIC COMPOUNDS
ORGANOMETALLIC COMPOUNDS
PHYSICAL PROPERTIES
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0000-0013 K
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE