1209.0688 (Keola Wierschem et al.)

Magnetic and nematic orderings in spin-1 antiferromagnets with
single-ion anisotropy    [PDF]

Keola Wierschem, Yasuyuki Kato, Yusuke Nishida, Cristian D. Batista, Pinaki Sengupta

We study a spin-one Heisenberg model with exchange interaction, J, uniaxial single-ion exchange anisotropy, D, and Zeeman coupling to a magnetic field, B, parallel to the symmetry axis. We com- pute the (D/J,B/J) quantum phase diagram for square and simple cubic lattices by combining an- alytical and Quantum Monte Carlo approaches, and find a transition between XY-antiferromagnetic and ferronematic phases that spontaneously break the U(1) symmetry of the model. In the language of bosonic gases, this is a transition between a Bose-Einstein condensate (BEC) of single bosons and a BEC of pairs. Our work opens up new avenues for measuring this transition in real magnets.

View original: http://arxiv.org/abs/1209.0688