TY - JOUR
T1 - Evidence for a metallic but unusual ground state in τ-conductors
AU - Murata, K.
AU - Konoike, T.
AU - Iwashita, K.
AU - Yoshino, H.
AU - Sasaki, T.
AU - Hiraki, K.
AU - Takahashi, T.
AU - Nishio, Y.
AU - Kajita, K.
AU - Papavassiliou, G. C.
N1 - Funding Information:
This work was carried out as a part of ‘Research for the Future’ project, JSPS-RFTF97P00105, supported by Japan Society for the Promotion of Science. One of the authors (TK) was supported by Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists.
PY - 2003/3/13
Y1 - 2003/3/13
N2 - The band calculation for the τ-conductors predicted the existence of a Fermi surface, which has a two-dimensional star-shaped 4-fold symmetry. Actually, both τ-(EDO-S,S-DMEDT-TTF)2(AuBr2)1+y and τ-(P-S,S-DMEDT-TTF)2(AuBr2)1+y (y ∼ 0.75) show metallic temperature dependence of resistivity (dR/dT > 0) below 300 K with a resistance upturn at 30-50 K. Below the temperature of resistance minimum, a large negative magnetoresistance (MR) suddenly appears in temperature, accompanied by a remarkable features such as the switching of the periodicity of the angular dependence of MR, large electronic specific heat coefficient γ (0.06 J/molK2). Lots of works have been devoted to clarify whether or not the low temperature electronic state is metal. Recently we could demonstrate a giant Shubnikov de Haas oscillation in both materials, which is a direct evidence for a metallic state. We note that the observed FSs were not consistent with the previous calculation. How this metallic state explains those remarkable features is still unsolved.
AB - The band calculation for the τ-conductors predicted the existence of a Fermi surface, which has a two-dimensional star-shaped 4-fold symmetry. Actually, both τ-(EDO-S,S-DMEDT-TTF)2(AuBr2)1+y and τ-(P-S,S-DMEDT-TTF)2(AuBr2)1+y (y ∼ 0.75) show metallic temperature dependence of resistivity (dR/dT > 0) below 300 K with a resistance upturn at 30-50 K. Below the temperature of resistance minimum, a large negative magnetoresistance (MR) suddenly appears in temperature, accompanied by a remarkable features such as the switching of the periodicity of the angular dependence of MR, large electronic specific heat coefficient γ (0.06 J/molK2). Lots of works have been devoted to clarify whether or not the low temperature electronic state is metal. Recently we could demonstrate a giant Shubnikov de Haas oscillation in both materials, which is a direct evidence for a metallic state. We note that the observed FSs were not consistent with the previous calculation. How this metallic state explains those remarkable features is still unsolved.
KW - Fermi surface
KW - Magnetic properties
KW - Negative magnetoresistance
KW - Organic conductor
KW - Shubnikov de Haas effect
KW - Transport properties
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U2 - 10.1016/S0379-6779(02)00369-7
DO - 10.1016/S0379-6779(02)00369-7
M3 - Conference article
AN - SCOPUS:0037435348
SN - 0379-6779
VL - 133-134
SP - 103
EP - 105
JO - Synthetic Metals
JF - Synthetic Metals
T2 - ISCOM 2001
Y2 - 10 September 2001 through 14 September 2001
ER -