Symmetry-protected topological phases in spinful bosons with a flat band
Symmetry-protected topological phases in spinful bosons with a flat band
复制标题
DOI：
10.1103/physrevresearch.3.023210
复制
发表时间：
2020-03
期刊：
影响因子：
--
通讯作者：
Hong Yi Shi Yang;H. Nakano;H. Katsura
中科院分区：
文献类型：
--
作者：
Hong Yi Shi Yang;H. Nakano;H. Katsura
我们从理论上证明了相互作用的对称性保护拓扑(SPT)相可以用超冷的自旋玻色子原子负载在能带结构底部具有平坦能带的晶格上来实现。这种体系中的SPT相由零温下的自旋涨落和电荷涨落共同决定。我们发现，在某些特殊情况下，这类系统的多体基态可以精确地记录下来，并且这些精确的基态可以作为SPT相的代表态。作为一个具体的例子，我们证明了锯齿链上的自旋-1玻色子可以处于受自旋旋转对称性或时间反转对称性保护的SPT相，并且这种SPT相是自旋涨落的结果。我们还表明，Kagome晶格上的自旋3玻色子可以处于受$D_2$点群对称性保护的SPT相中，但该SPT相是电荷涨落的结果。
We theoretically demonstrate that interacting symmetry-protected topological (SPT) phases can be realized with ultracold spinful bosonic atoms loaded on lattices which have a flat band at the bottom of the band structure. The SPT phases in such systems are determined by both spin and charge fluctuations at zero temperature. We find that the many-body ground states of such systems can be exactly written down in some special cases, and these exact ground states turn out to serve as representative states of the SPT phases. As a concrete example, we demonstrate that spin-1 bosons on a sawtooth chain can be in an SPT phase protected by $\mathbb{Z}_2 \times \mathbb{Z}_2$ spin rotation symmetry or time-reversal symmetry, and this SPT phase is a result of spin fluctuations. We also show that spin-3 bosons on a kagome lattice can be in an SPT phase protected by $D_2$ point group symmetry, and this SPT phase is however a result of charge fluctuations.