On the Incommensurate Phase of Pure and Doped Spin-Peierls System CuGeO_3

TL;DR

This paper investigates the incommensurate phase of CuGeO_3, a spin-Peierls system, analyzing phase transitions, critical behavior, and effects of doping on order and correlations using Landau theory.

Contribution

It provides a theoretical analysis of the incommensurate phase in CuGeO_3, including effects of doping and disorder on phase stability and correlation decay.

Findings

Doping destroys long-range order in the incommensurate phase.

Weak disorder leads to algebraic decay of correlations.

Critical behavior and soliton width are characterized.

Abstract

Phases and phase transitions in pure and doped spin-Peierls system CuGeO_3 are considered on the basis of a Landau-theory. In particular we discuss the critical behaviour, 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.