Dr. Ribhu Kaul
Microsoft Station-Q at UCSB
Destruction of Neel order in quantum anti-ferromagnets
Anti-ferromagnetism is ubiquitous in nature, the most famous example being the undoped parent materials of the cuprate high-Tc superconductors. The simplest model description of this material is a two-dimensional square lattice of S=1/2 spins; each spin interacting with its nearest neighbors. Consistent with experimental results on the cuprates this model develops collinear Neel ordering at low-temperatures. I will discuss the interesting physical consequences of weakening and the eventual destruction of the Neel order in insulating two-dimensional square lattice anti-ferromagnets with half-integer spin per unit cell and the possibility of quantum criticality. The physics of a dilute concentration of non-magnetic impurities is remarkably rich in such magnets with strong quantum fluctuations, and provides a novel way to probe the complex physics of these systems.