1202.3908 (Derek Larson et al.)

Quantum antagonism of ferromagnetic order    [PDF]

Derek Larson, Ying-Jer Kao

We study the effects of competing order in a frustrated quantum magnet. By
shifting the distribution of the nearest neighbor {\pm}J interaction in a
three-dimensional Edwards-Anderson spin glass, one can produce
anti-ferromagnetic, glassy, and ferromagnetic (diagonal) phases. We add quantum
mechanical exchange terms which allows, additionally, for superfluid
(off-diagonal) ordering. The interplay between these types of order produces
rich behavior, and we look at the effect on the transition between diagonal
orders: moving from the spin glass phase to either ferromagnetic or
antiferrmagnetic phases. Quantum Monte Carlo simulation results using the worm
algorithm show that the spin exchange terms asymetrically favor the
antiferromagnetic state. Thus, the phase boundaries shift to increase the
antiferromagnetic region and diminish the ferromagnetic region.

View original: http://arxiv.org/abs/1202.3908