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Electrical Properties of (DEPE) (TCNQ) 4
Author(s) -
Somoano R. B.,
Hadek V.,
Yen S. P. S.,
Rembaum A.,
Hsu C. H.,
Deck R. J.,
Datta T.,
Hermann A. M.
Publication year - 1977
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.2220810130
Subject(s) - seebeck coefficient , monoclinic crystal system , tetracyanoquinodimethane , electrical resistivity and conductivity , materials science , phase (matter) , metal , analytical chemistry (journal) , crystallography , condensed matter physics , chemistry , crystal structure , thermal conductivity , electrical engineering , physics , molecule , organic chemistry , chromatography , metallurgy , composite material , engineering
Conductivity measurements are performed on single crystals of two phases of (1,2‐di(N‐ethyl‐4‐pyridinium)ethylene 2+ ) (7,7,8,8‐tetracyanoquinodimethane) 4 2− , (DEPE) (TCNQ) 4 . Conductivities are determined by four probe and Montgomery methods, and the highest values measured are those along the b 0 ‐axis for the monoclinic phase (I) crystals, ≈ 50 (Ω cm) −1 at room temperature. The resistivities are in general exponentially activated (semiconducting behavior). Thermoelectric power measurements are performed along the b 0 ‐axis of phase I crystals and the thermopower tends to saturate at high temperatures to −60 μV/K, characteristic of a quarter‐filled correlated band. No evidence for the existence of a stable metallic state reported by Ashwell et al. was found. The preliminary crystal structures of both phases are discussed.