Nematicity Squared: Emergent Ising Phases in Strongly Correlated Materials
| Date/Time: | Monday, 08 Feb 2016 from 4:10 pm to 5:00 pm |
|---|---|
| Location: | Physics 0003 |
| Phone: | 515-294-5441 |
| Channel: | College of Liberal Arts and Sciences |
| Actions: | Download iCal/vCal | Email Reminder |
Abstract: The development of order in strongly correlated materials is often complicated by competing phases, low dimensionality or disorder, and the fluctuations of ordered phases can play as important a role as the phase itself. One recent theme is the residual orders that can be left behind when fluctuations destroy a more fragile phase. Often the fragile phase breaks both continuous and discrete symmetries, and while fluctuations restore the continuous symmetries, they leave behind a phase that still breaks the discrete symmetries. Most famously, this process occurs in the high temperature iron-based superconductors, where the parent stripe magnetic order breaks discrete lattice rotational as well as continuous spin symmetries, giving rise to a residual nematic phase that breaks only the discrete rotational symmetries. Here, this residual nematic order is described by a single Ising order parameter. In this talk, I will introduce two related materials, Fe1+yTe and BaTi2Sb2O, whose parent magnetic order is now a "double stripe" phase, whose residual nematic orders are described by not one, but two Ising order parameters. We will explore the resulting phase diagram, including how these materials fit in, and discuss the consequences of multiple Ising order parameters.