On the incommensurate phase of the pure and doped spin-peierls system CuGeO₃

Abstract

Phases and phase transitions in the pure and doped spin-Peierls system CuGeO₃ are considered on the basis of a Landau theory. In particular, we discuss the critical behavior, the soliton width, and the low-temperature specific heat of the incommensurate phase. We show that dilution leads always to the destruction of long-range order in this phase, which is replaced by an algebraic decay of correlations if the disorder is weak.