Events at Physics |
Events During the Week of June 3rd through June 10th, 2012
Monday, June 4th, 2012
- Condensed Matter Theory Group Seminar
- Magnetic Ordering of the Heisenberg J1 – J2 – J3 Model
- Time: 4:30 pm
- Place: 5310 Chamberlin
- Speaker: Samuel Ducatman, UW-Madison
- Abstract: We calculated the ground state energies, spin wave spectrum, and investigated the stability of the diagonal double stripe and orthogonal double stripe magnetic orderings of the J1 - J2 - J3 Heisenberg square lattice. We assumed a small J1 and J2 <2J3, and analytically calculated the quantum corrections with a four sublattice model. By investigating the spectrum around the goldstone point (π/2, - π/2), we found that the diagonal double stripe phase is unstable. We also considered how the orthogonal double stripe phase, found to be stable, competes with spiral phase. We compared our results to previous simulations and neutron scattering experiments of FeTe, which is thought to have a double stripe phase.
Tuesday, June 5th, 2012
- No events scheduled
Wednesday, June 6th, 2012
- No events scheduled
Thursday, June 7th, 2012
- R. G. Herb Condensed Matter Seminar
- Chiral Fermi liquids
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Dmitrii Maslov, University of Florida
- Abstract: Chirality ("handedness") of electron spins is a hallmark of many systems of current interest, including two-dimensional electron gases (2DEG) in semiconductor heterostructures, surface (edge) states of topological insulators, and graphene (in the last example, it is a pseudo- rather than real spin which is chiral). While by now we know a lot about single-particle properties of these systems, their many-body properties are just starting to be explored. In this talk, I will discuss a general phenomenology of non-SU(2) invariant Fermi liquids. The main prediction of the phenomenological approach--complemented by a microscopic calculation--is the existence of a new type of collective modes: "chiral spin waves", which we propose to observe experimentally in a semiconductor hetetorostructure with an in-plane modulation of the spin-orbit interaction. I will also discuss how spin-orbit interaction affects the non-analytic corrections to the Fermi-liquid behavior. In particular, a non-analytic dependence of the spin susceptibility on the momentum is shown to result in a new type of long-range RKKY interaction between localized moments embedded into a 2DEG, with a period given by the spin relaxation length rather the Fermi wavelength.
- Host: Chubukov
Friday, June 8th, 2012
- Cosmology Journal Club
- An Informal discussion about a broad variety of arXiv papers related to Cosmology
- Time: 12:00 pm
- Place: 5242 Chamberlin Hall
- Abstract: Please visit the following link for more details:
http://cmb.physics.wisc.edu/journal/index.html
Please feel free to bring your lunch!
If you have questions or comments about this journal club, would like to propose a topic or volunteer to introduce a paper, please email Le Zhang (lzhang263@wisc.edu) - Host: Peter Timbie