G. Grinstein, Terence Hwa, et al.
Physical Review A
Simple, nearest-neighbor XY models on unfrustrated lattices with competing ferromagnetic [cos()] and nematic [cos(2)] interactions are studied. For sufficiently strong competition, this model exhibits four phases in spatial dimension d=3 and five in d=2, including in both cases a new phase with extensive zero-point entropy. As a result of this zero-point entropy the system does not acquire perfect order even in the zero-temperature limit. The model has vortices of both irrational and integer winding number; in d=2 their unbinding mediates the phase transitions, which are all of the Kosterlitz-Thouless type. © 1986 The American Physical Society.
G. Grinstein, Terence Hwa, et al.
Physical Review A
G. Grinstein, G.A. Held, et al.
Journal of Magnetism and Magnetic Materials
D.H. Lee, G.T. Zimanyi
Physical Review B
G. Grinstein, M.A. Muñoz, et al.
Physical Review Letters