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Pressure‐induced insulator–metal transition in a novel layer metalloorganic structure
Author(s) -
Ovsyannikov Sergey V.,
Shchennikov Vladimir V.,
Titov Alexander N.,
Uwatoko Yoshiya
Publication year - 2007
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.200672531
Subject(s) - cobaltocene , intercalation (chemistry) , seebeck coefficient , van der waals force , metal , materials science , cobalt , metal–insulator transition , condensed matter physics , thermoelectric effect , electrical resistivity and conductivity , chemistry , crystallography , composite material , inorganic chemistry , thermodynamics , molecule , physics , thermal conductivity , metallurgy , organic chemistry , quantum mechanics , metallocene , polymerization , polymer
A novel layer metalloorganic structure (Co(η 5 ‐C 5 H 5 ) 2 ) 0.25 TiSe 2 has been synthesized by intercalation of the cobaltocene, Co(η 5 ‐C 5 H 5 ) 2 [bis(eta‐5‐cyclopentadienyl)cobalt] (a representative of the metallocenes M(η 5 ‐C 5 H 5 ) 2 where M – is a metal) into van‐der‐Waals gaps of TiSe 2 matrix. The papers reports a study of the electrical resistance R , thermoelectric power S (Seebeck effect), and contraction of a sample's thickness (compressibility) under almost continuous variation of quasihydrostatic pressure P within 0–20 GPa at room temperature. We observed a gradual decrease of R ( P ) by ∼8 orders to 20 GPa. About P ∼ 10 GPa we established both an abrupt change of d R /d P and inversion of S from the electronic to the holes type of conductivity. To P ∼ 16 GPa the intercalate became a metal and exhibited a “close to zero” S , which was kept down to 8 GPa on decompression; all pressure‐induced changes were reversible. The synthesized compound (Co(η 5 ‐C 5 H 5 ) 2 ) 0.25 TiSe 2 is a novel functional material for wide application. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)