The discussion centers on the mechanisms behind stripe phases in superconductivity, particularly in relation to charge density waves (CDW) and spin density waves (SDW). Participants explore theoretical aspects, potential origins, and related phenomena in various materials, including RMnO3 compounds.
Participants express various viewpoints regarding the mechanisms and implications of stripe phases, CDW, and SDW, indicating that multiple competing views remain and the discussion is unresolved.
Some limitations include the dependence on definitions of terms like "instability" and "order parameter," as well as unresolved aspects of the phenomenological models discussed.
This discussion may be of interest to researchers and students in condensed matter physics, particularly those focused on superconductivity, charge density waves, and spin density waves.
So you mention long-range. From the literature, I saw that CDW/SDW is described as the "order parameter" in Landau-Ginzburg model. What kind of symmetry breaking is involved? Can I say translational symmetry? Which reference do you suggest if I want to understand more about its phenomenological model and the origin of CDW/SDW?M Quack said:Stripe phases or charge ordering also occur in RMnO3 compounds.
The usual origin of a CDW or SDW is an instability due nesting of the Fermi surface, i.e. parts of the Fermi surface being parallel to each other. The ordering wave vector at the critical temperature is then the distance in reciprocal space between these two parts of the Fermi surface.
In inelastic neutron scattering you can see phonon or magnons going soft at the ordering wave vector well above the transition temperature. When the phonon/magnon energy goes to zero, the system becomes unstable and long range order sets in.