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Hints for the metallic phase in Rb 4 C 60 under pressure
Author(s) -
Francis E. A.,
Kuntscher C. A.
Publication year - 2014
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201451165
Subject(s) - materials science , metal , infrared , closing (real estate) , metal–insulator transition , nanoscopic scale , infrared spectroscopy , phase (matter) , alkali metal , insulator (electricity) , spectroscopy , condensed matter physics , charge (physics) , analytical chemistry (journal) , chemistry , nanotechnology , physics , optics , optoelectronics , metallurgy , organic chemistry , chromatography , quantum mechanics , political science , law
The alkali fulleride Rb 4 C 60 was investigated by infrared spectroscopy under high pressure, to study the vibrational and electronic excitations. The material exhibits a bad metal behavior in the measured pressure range (0.8–8 GPa). With increasing pressure the Drude term in the far‐infrared region increases, which signals an increasing metallic character. By following the optical excitations under pressure, we could attribute the underlying mechanism of the pressure‐induced insulator‐to‐metal transition in Rb 4 C 60 to the closing of the charge gap, and the nanoscale phase separation scenario discussed in the literature seems to be unlikely.