Abstract
The interplay of alternating potential and dimerization (u) has been examined for the spin density wave (SDW) state in a quasi-one-dimensional system at quarter-filling, which is expressed in terms of θ, a phase of the SDW. By taking account of the dimerization energy u2 /(2g) with an effective coupling constant g, we evaluate critical temperatures, Tc, Ts and Tu, corresponding to the onset of Δc (∝ ‹ cos θ › ), Δs (∝ ‹ sin θ › ) and u, respectively. Two kinds of noticeable critical temperatures of the SDW states are obtained where Tc > Ts = Tu for g < gc and Tu > Tc = Ts for g > gc. The quantity gc is increased by both the alternating potential and the interchain coupling. The relevance to the SDW state in (EDT-TTF)2AuBr2 salt is discussed.
