Hamburg 2001 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 6: Postersitzung I: Josephsonkontakte und SQUIDs, Supraleitung: Theorie, Korrelierte Elektronen, Niederdimensionale Systeme, Magnetotransport, Quantenhalleffekt, Kohlenstoff-Nanoröhrchen, Quantenflüssigkeiten
TT 6.44: Poster
Montag, 26. März 2001, 14:30–17:00, Rang S\ 3
Correlation gap in the optical spectra of the two-dimensional organic metal (BEDT-TTF)4[Ni(dto)2] — •Martin Dressel1, P. Haas1, E. Grießhaber1, M. Schiller1, W. Schmidt1, E. Balthes1, B. Gorshunov1, D. Schweitzer1, F. Assaad1, T. Klausa2, I. Heinen2, and W. Strunz2 — 1FB Physik, Universität Stuttgart — 2FB Chemie, Universität Heidelberg
Optical reflection measurements within the highly conducting
(a,b)-plane of the organic metal
(BEDT-TTF)4[Ni(dto)2] reveal the gradual development
of a sharp feature (in both directions) at around 200 cm−1 as
the temperature is reduced below 150 K. Below this frequency
a narrow Drude-like response is observed which accounts for
the metallic behavior. Since de Haas-van Alphen oscillations
at low temperatures confirm band structure calculations of
bands crossing the Fermi energy, we assign the observed
behavior to a two-dimensional metallic state in the proximity
of a correlation induced metal-insulator transition,
i.e. the system approaches a Mott metal-insulator transition
in two-dimensions.
P. Haas, et al. Phys. Rev. B 62, R14673 (2000)