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Correlation gap in the optical spectra of the two-dimensional organic metal (BEDT-TTF)_4[Ni(dto)_2]

P. Haas·E. Griesshaber·B. Gorshunov·D. Schweitzer·M. Dressel·F. F. Assaad
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Abstract

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 at around 200 cm 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-von 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.

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P. Haas, E. Griesshaber, B. Gorshunov, D. Schweitzer, M. Dressel, F. F. Assaad. 2001-04-04. Correlation gap in the optical spectra of the two-dimensional organic metal (BEDT-TTF)_4[Ni(dto)_2]. https://doi.org/10.1103/physrevb.62.r14673

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