Events at Physics |
Events During the Week of January 15th through January 22nd, 2012
Monday, January 16th, 2012
- Martin Luther King Day
Tuesday, January 17th, 2012
- No events scheduled
Wednesday, January 18th, 2012
- Physics Department Colloquium
- Title to be announced
- Speaker: No Colloquium -- please remove
Thursday, January 19th, 2012
- R. G. Herb Condensed Matter Seminar
- Nematic order and magnetism in the high-temperature iron-based superconductors
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Rafael Fernandes, Columbia University
- Abstract: The recent discovery of iron-based compounds displaying superconductivity at nearly 60K opened a new direction in the research of high-temperature superconductors. Much of the interest lies in understanding not only their superconducting pairing mechanism, but also their normal state properties. In this talk, I will show that emergent Ising-nematic degrees of freedom are present in these systems over wide temperature and doping ranges, fundamentally affecting their macroscopic properties and explaining several behaviors observed experimentally. Starting from a microscopic electronic model, I will demonstrate that the nematic state has magnetic origin, and is associated with a spontaneous tetragonal symmetry-breaking. I will discuss the phase diagrams resulting from this model, and how the elastic properties are affected by nematic fluctuations. I will also show that the scattering of electrons by impurities and by spin fluctuations in the nematic phase leads to an anisotropy in the resistivity, whose sign changes from electron-doped to hole-doped compounds.
- Host: Chubukov
Friday, January 20th, 2012
- No events scheduled