Phase interference in antiferromagnetic quantum tunneling with an   arbitrarily directed magnetic field
  The quantum interference effects induced by the topological phase are studied analytically in biaxial antiferromagnets with an external magnetic field at an arbitrarily angle. This study provides a nontrivial generalization of the Kramers degeneracy for equivalent double-well system to coherently spin tunneling at ground states as well as low-lying excited states for antiferromagnetic system with asymmetric twin barriers. The spin-phase interference effects are found to depend on the orientation of the magnetic field distinctly. 
Rong Lu, Hui Pan, Jia-Lin Zhu, and Bing-Lin Gu (Center for Advanced   Study, Tsinghua University, Beijing)