Supersolid states in a spin system: Phase diagram and collective excitations
Supersolid states in a spin system: Phase diagram and collective excitations
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自旋系统中的超固态：相图和集体激发
DOI：
10.1103/physrevb.88.224404
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发表时间：
2013
影响因子：
3.7
通讯作者：
H. Aoki
中科院分区：
文献类型：
--
作者：
Y. Murakami;T. Oka;H. Aoki
类似于超固体的相可以在自旋系统中实现。在这里，我们得到了一个沮丧的二聚体自旋1/2系统的正方形晶格的相图和研究集体激发光谱，重点是超固态（SS）。在交换相互作用和磁场的参数空间上的相图中，我们发现，在SS相的顶部，在玻色-哈伯德模型中没有对应物的相，并且在玻色-哈伯德模型中SS增强发生的区域，该状态成为主导。然后，我们研究了激发谱和自旋-自旋相关，这可以通过中子散射实验检测到。我们得到了自旋波速度的解析表达式，它符合流体动力学关系。计算了自旋-自旋关联函数中激发模的强度，讨论了它们在超固态和超流态中的变化。
Phases analogous to supersolids can be realized in spin systems. Here we obtain the phase diagram of a frustrated dimer spin-1/2 system on a square lattice and study the collective excitation spectra, focusing on the supersolid state (SS). In the phase diagram on a parameter space of the exchange interaction and magnetic field, we find, on top of the SS phase, a phase that has no counterpart in the Bose Hubbard model and this state becomes dominant at the region where the enhancement of SS occurs in the bose Hubbard model. We then investigate the excitation spectrum and spin- spin correlation, which can be detected by neutron scattering experiments. We obtain an analytic expression for the spin wave velocity, which agrees with hydrodynamic relations. The intensity of excitation modes in the spin-spin correlation function is calculated and their change in the supersolid and superfluid states is discussed.