Speaker
Prof.
Michel Gingras
(University of Waterloo)
Description
In some magnetic systems, known as frustrated magnets, the lattice geometry or the competition between different spin-spin interactions can lead to a sub-exponentially large number of accidentally degenerate classical ground states, or false vacuua, and thus a sort of landscape problem for condensed matter physicists. Order-by-disorder (OdD) is a concept of central importance in the field of frustrated magnetism. Saddled with large accidental degeneracies, a subset of states, those that support the largest quantum and/or thermal fluctuations, may be selected to form true long-range order. ObD has been discussed extensively on the theoretical front for over 30 years and proposed to be at play in a number of experimental settings. Unfortunately, convincing demonstrations of OBD in real materials have remained scarce. In this talk, I will review the phenomena of thermal and quantum of order-by-disorder and discuss how recent work may have evinced compelling evidence for ObD in some frustrated XY pyrochlore antiferromagnetic materials.
Author
Prof.
Michel Gingras
(University of Waterloo)
