Sengupta P, Batista C D
Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Phys Rev Lett. 2007 Nov 23;99(21):217205. doi: 10.1103/PhysRevLett.99.217205. Epub 2007 Nov 20.
We consider an S=1 Heisenberg chain with strong exchange (Delta=J(z)/J(perpendicular)) and single-ion uniaxial anisotropy (D) in a magnetic field (B) along the symmetry axis. The low-energy spectrum is described by an effective S=1/2 XXZ model that acts on two different low-energy sectors for a finite range of fields. The vacuum of each sector exhibits Ising-like antiferromagnetic ordering coexisting with the finite spin stiffness obtained from the exact solution of the XXZ model. In this way, we demonstrate the existence of a spin supersolid phase. We also compute the full Delta-B quantum phase diagram using a quantum Monte Carlo method.
我们考虑一个具有强交换作用（$\Delta = J(z)/J(\perp)$）以及沿对称轴方向磁场（$B$）中的单离子单轴各向异性（$D$）的$S = 1$海森堡链。低能谱由一个有效的$S = 1/2$ XXZ模型描述，该模型在有限磁场范围内作用于两个不同的低能扇区。每个扇区的真空态呈现出类伊辛反铁磁序，且与从XXZ模型精确解得到的有限自旋刚度共存。通过这种方式，我们证明了自旋超固体相的存在。我们还使用量子蒙特卡罗方法计算了完整的$\Delta - B$量子相图。
