Schechter Moshe, Laflorencie Nicolas
Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, V6T 1Z1.
Phys Rev Lett. 2006 Sep 29;97(13):137204. doi: 10.1103/PhysRevLett.97.137204. Epub 2006 Sep 28.
Anisotropic dipolar systems are considered. Such systems in an external magnetic field are expected to be a good experimental realization of the transverse field Ising model. With random interactions, this model yields a spin glass to paramagnet phase transition as a function of the transverse field. We show that the off-diagonal dipolar interaction, although effectively reduced, induces a finite correlation length and thus destroys the spin-glass order at any finite transverse field. We thus explain the behavior of the nonlinear susceptibility in the experiments on LiHo(x)Y(1-x)F(4), and argue that a crossover to the paramagnetic phase, and not quantum criticality, is observed.
考虑了各向异性偶极系统。这种处于外磁场中的系统有望成为横向场伊辛模型的一个良好实验实现。对于具有随机相互作用的情况，该模型会产生一个作为横向场函数的从自旋玻璃到顺磁体的相变。我们表明，尽管对角外偶极相互作用有效减小，但它会诱导出一个有限的关联长度，从而在任何有限横向场下破坏自旋玻璃序。因此，我们解释了在LiHo(x)Y(1 - x)F(4)实验中非线性磁化率的行为，并认为观察到的是向顺磁相的转变，而非量子临界性。
