Abstract of talk
The pyrochlore lattice, a network of corner-sharing tetrahedra, is one of the most pervasive crystalline architectures in nature that supports geometrical frustration. We and others have been interested in a family of rare earth pyrochlore magnets, that can display quantum S=1/2 magnetism on such a lattice. The ground states for some of these materials may be described by a model known as "spin ice", a model with the same frustration and degeneracy as solid ice (the kind you might skate on in Canada), as well as by a quantum version of this model known as "quantum spin ice" that possesses an emergent quantum electrodynamics. I'll describe how this comes about and how we can understand these materials, with an emphasis on modern neutron scattering. I'll also discuss a generalized phase diagram for the ground states of these materials, with emphasis on the Yb2Ti2O7, Er2Ti2O7, and Er2Pt2O7.
Brief biography of speaker
Prof. Bruce D. Gaulin is an experimental condensed matter physicist, working in the general area of scattering studies of exotic ground states in new, mostly magnetic, materials. His research group and collaborators make new materials which show promise for hosting interesting and exotic ground states, and then take these materials to forefront neutron and x-ray scattering facilities in North America and around the world. He is currently Distinguished University Professor, Bertram Brockhouse Chair, and Director of the Brockhouse Institute for Materials Research at McMaster University, Canada. Bruce D. Gaulin began his academic career as Assistant Professor in 1988 and was promoted to Associate Professor at 1992. In 1998, he was appointed as Bertram Brockhouse Chair in the Physics of Materials at McMaster University and recently reappointed to this position for the 2019-2024 term. In 2009, he was named Director of the Brockhouse Materials Research Center, a leadership position he currently holds and honored as Distinguished University Professor of McMaster University in 2017. He has published more than 210 international academic journal papers to date with more than 6000 citations and an h-index of 41. His record of research excellence has garnered him important honors including Fellow, Neutron Scattering Society of America (2014), Fellow of the Royal Society of Canada (2011), and Fellow of the American Physical Society (2006).