抄録
A role of interchain hopping in quasi-one-dimensional (Q-1D) electron systems is investigated by extending the Kadanoff–Wilson renormalization group of one-dimensional (1D) systems to Q-1D systems. This scheme is applied to the extended Hubbard model to calculate the temperature (T) dependence of the magnetic susceptibility, χ(T). The calculation is performed by taking into account not only the logarithmic Cooper and Peierls channels, but also the non-logarithmic Landau and finite momentum Cooper channels, which give relevant contributions to the uniform response at finite temperatures. It is shown that the interchain hopping, t⊥, reduces χ(T) at low temperatures, while it enhances χ(T) at high temperatures. This notable t⊥ dependence is ascribed to the fact that t⊥ enhances the antiferromagnetic spin fluctuation at low temperatures, while it suppresses the 1D fluctuation at high temperatures. The result is at variance with the random-phase-approximation approach, which predicts an enhancement of χ(T) by t⊥ over the whole temperature range. The influence of both the long-range repulsion and the nesting deviations on χ(T) is further investigated. We discuss the present results in connection with the data of χ(T) in the (TMTTF)2X and (TMTSF)2X series of Q-1D organic conductors, and propose a theoretical prediction for the effect of pressure on magnetic susceptibility.
