Stiffness from disorder in frustrated quasi-two-dimensional magnets
Stiffness from disorder in frustrated quasi-two-dimensional magnets
Gia-Wei Chern, LANL
Date and time:
Thu, Mar 26, 2015 - 11:30am
Refreshments at 11:15am
Location:
LGRT 1033
Category:
Condensed Matter Seminar
Abstract:
Frustrated magnetism has become an extremely active field of research. The concept of geometrical frustration dates back to Wannier’s 1950 study of Ising antiferromagnet on the triangular lattice. This simple system illustrates many defining characteristics of a highly frustrated magnet, including a macroscopic ground-state degeneracy and the appearance of power-law correlations without criticality. In this talk I will discuss a simple generalization of the triangular Ising model, namely, a finite number of vertically stacked triangular layers. Our extensive numerical simulations reveal a low temperature reentrance of two Berezinskii-Kosterlitz-Thouless transitions. In particular, I will discuss how short-distance spin-spin correlations can be enhanced by thermal fluctuations, a phenomenon we termed stiffness from disorder. This is a generalization of the well-known order-by-disorder mechanism in frustrated systems. I will also present an effective field theory that quantitatively describes the low-temperature physics of the multilayer triangular Ising antiferromagnet.
Department of Physics