Phase transitions in models for coupled charge-density waves

Minchul Lee, Eun Ah Kim, Jong Soo Lim, M. Y. Choi

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2 Scopus citations


Various phase transitions in models for coupled charge-density waves are investigated by means of the ε expansion, mean-field theory, and Monte Carlo simulations. At zero temperature the effective action for the system with appropriate commensurability effects is mapped onto the three- or four-dimensional XY model, depending on spatiotemporal fluctuations, under the corresponding symmetry-breaking fields. It is revealed that the three- and four-dimensional systems display a single transition between the clock order (with broken ZM symmetry) and disorder. The nature of the phase transition depends crucially on the commensurability factor M: For M≥4, in particular, the transition belongs to the same university class as the XY model. On the other hand, in the presence of misfit causing frustration in the charge-density wave, the interchain coupling is observed to favor either the commensurate state or the incommensurate state depending on the initial configuration; this gives rise to hysteresis around the commensurate-incommensurate transition. Boundaries separating such phases with different symmetries are obtained in the parameter space consisting of the temperature, symmetry-breaking field, fluctuation strength, interchain coupling, and misfit.

Original languageEnglish
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number11
StatePublished - 22 Mar 2004


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