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Stripe Phase

by stephenhky
Tags: phase, stripe
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stephenhky
#1
Apr22-12, 05:39 PM
P: 33
It was observed that stripe phases appear in some high-temperature superconductivity and it is believed to be related to strongly-correlated electron system. Is the mechanism of the formation of stripe phase completely known? Does it appear in non-superconducting systems as well?
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stephenhky
#2
Apr26-12, 03:02 PM
P: 33
And does anybody know about charge density wave (CDW) and spin density wave (SDW)?

My question is... what is the mechanism that induces the instability of CDW and SDW?
M Quack
#3
Apr26-12, 05:32 PM
P: 660
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.

stephenhky
#4
Apr26-12, 05:43 PM
P: 33
Stripe Phase

Quote Quote by M Quack View Post
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.
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?

Thanks!
M Quack
#5
Apr28-12, 05:50 AM
P: 660
Correct, translational symmetry is broken.

I have to check for a good reference that covers the subject.

The prototype SDW/CDW is in chromium metal, there is plenty of literature on that.


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