TY - JOUR
T1 - Theory of the β-type organic superconductivity under uniaxial compression
AU - Suzuki, Takeo
AU - Onari, Seiichiro
AU - Ito, Hiroshi
AU - Tanaka, Yukio
PY - 2011/9
Y1 - 2011/9
N2 - We study theoretically the shift of the superconducting transition temperature (Tc) under uniaxial compression in β-type organic superconductors, β-(BEDT-TTF)2I3 and β-(BDA-TTP)2X (X = SbF6, AsF6), in order to clarify the electron correlation, the spin frustration, and the effect of dimerization. The transfer integrals are calculated by the extended Hückel method assuming the uniaxial strain, and the superconducting state mediated by the spin fluctuation is solved using Eliashberg's equation with the fluctuation-exchange approximation. The calculation is carried out on both the dimerized (one-band) and nondimerized (two-band) Hubbard models. We have found that (i) the behavior of Tc in β-(BEDT-TTF)2I3 with a stronger dimerization is well reproduced by the dimer model, while that in weakly dimerized β-BDA-TTP salts is rather well reproduced by the two-band model, and (ii) the competition between the spin frustration and the effect induced by the fluctuation is important in these materials, which causes the nonmonotonic shift of Tc against uniaxial compression.
AB - We study theoretically the shift of the superconducting transition temperature (Tc) under uniaxial compression in β-type organic superconductors, β-(BEDT-TTF)2I3 and β-(BDA-TTP)2X (X = SbF6, AsF6), in order to clarify the electron correlation, the spin frustration, and the effect of dimerization. The transfer integrals are calculated by the extended Hückel method assuming the uniaxial strain, and the superconducting state mediated by the spin fluctuation is solved using Eliashberg's equation with the fluctuation-exchange approximation. The calculation is carried out on both the dimerized (one-band) and nondimerized (two-band) Hubbard models. We have found that (i) the behavior of Tc in β-(BEDT-TTF)2I3 with a stronger dimerization is well reproduced by the dimer model, while that in weakly dimerized β-BDA-TTP salts is rather well reproduced by the two-band model, and (ii) the competition between the spin frustration and the effect induced by the fluctuation is important in these materials, which causes the nonmonotonic shift of Tc against uniaxial compression.
KW - Organic superconductor
KW - Spin fluctuation
KW - Spin frustration
KW - Superconductivity
KW - Uniaxial compression
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U2 - 10.1143/JPSJ.80.094704
DO - 10.1143/JPSJ.80.094704
M3 - Article
AN - SCOPUS:80052394268
SN - 0031-9015
VL - 80
JO - journal of the physical society of japan
JF - journal of the physical society of japan
IS - 9
M1 - 094704
ER -