Z_2 topological order near the Neel state of the square lattice antiferromagnet

We classify quantum states proximate to the semiclassical Neel state of the spin S=1/2 square lattice antiferromagnet with two-spin near-neighbor and four-spin ring exchange interactions. Motivated by a number of recent experiments on the cuprates and the iridates, we examine states with Z_2 topological order, an order which is not present in the semiclassical limit. Some of the states break one or more of reflection, time-reversal, and lattice rotation symmetries, and can account for the observations. We discuss implications for the pseudogap phase.

Event Type: 
Scientific Area(s): 
Event Date: 
Thursday, May 18, 2017 - 10:00 to 11:30
Alice Room
Room #: