Nonequilibrium quantum criticality in bilayer itinerant ferromagnets

Details Nonequilibrium quantum criticality in bilayer itinerant ferromagnets Nonequilibrium quantum criticality in bilayer itinerant ferromagnets

2009-11-05

arxiv.org/abs/0911.1133v2

Phys. Rev. B 81, 125430 (2010)

Physics

Condensed Matter

Strongly Correlated Electrons

20+ pages, 3 figures; Revised version as accepted by PRB, added figure of mean field phase diagram

Scientific paper

10.1103/PhysRevB.81.125430

We present a theory of nonequilibrium quantum criticality in a coupled bilayer system of itinerant electron magnets. The model studied consists of the first layer subjected to an inplane current and open to an external substrate. The second layer is closed and subject to no direct external drive, but couples to the first layer via short-ranged spin exchange interaction. No particle exchange is assumed between the layers. Starting from a microscopic fermionic model, we derive an effective action in terms of two coupled bosonic fields which are related to the magnetization fluctuations of the two layers. When there is no interlayer coupling, the two bosonic modes possess different dynamical critical exponents z with z=2 (z=3) for the first (second) layer. This results in multi-scale quantum criticality in the coupled system. It is shown that the linear coupling between the two fields leads to a low energy fixed point characterized by the larger dynamical critical exponent z=3. The perturbative renormalization group is used to compute the correlation length in the quantum disordered and quantum critical regimes. We also derive the stochastic dynamics obeyed by the critical fluctuations in the quantum critical regime. Comparing the nonequilibrium situation to the thermal equilibrium scenario, where the whole system is at a temperature T, we find that the nonequilibrium drive does not always play the role of temperature.

Affiliated with

Also associated with

No associations

Rating

Nonequilibrium quantum criticality in bilayer itinerant ferromagnets does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Nonequilibrium quantum criticality in bilayer itinerant ferromagnets, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nonequilibrium quantum criticality in bilayer itinerant ferromagnets will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-390388