Electron correlations and $T$-breaking density wave order in a $\mathbb{Z}_2$ kagome metal
Electron correlations and $T$-breaking density wave order in a $\mathbb{Z}_2$ kagome metal
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发表时间：
2021-05
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通讯作者：
C. Setty;Haoyu Hu;Lei Chen;Q. Si
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作者：
C. Setty;Haoyu Hu;Lei Chen;Q. Si
最近在Kagome金属方面有了广泛的发展，如T$m$X$n$(T=Fe，Co和X=Sn，Ge)和$A$V$3$Sb$5$($A=$Cs，K，Rb)。一个新出现的问题是，当拓扑结构上的{非平凡}带穿过费米能级时，相关相位的性质。在这里，我们考虑了Kagome晶格上存在自旋-轨道耦合的扩展Hubbard模型，该模型包括具有相反Chern数的Kramer带，它们在能带结构中是孤立的。我们在时间反转(T)对称格子描述中构造了一个有效的模型。我们确定了该模型的相关相，并在相图中确定了密度-波级数。我们证明了这个序是T破缺的，它源于Wannier轨道缺少一个共同的Wannier中心--一个潜在的$Z_2$拓扑的指纹。讨论了我们的结果对Kagome金属的关联物理的影响。
There have been extensive recent developments on kagome metals, such as T$_m$X$_n$ (T= Fe, Co and X= Sn, Ge) and $A$V$_3$Sb$_5$ ($A=$ Cs, K, Rb). An emerging issue is the nature of correlated phases when topologically \textit{non-trivial} bands cross the Fermi level. Here, we consider an extended Hubbard model on the kagome lattice in the presence of spin-orbit couplings, involving a Kramer's pair of bands that have opposite Chern numbers and are isolated in the band structure. We construct an effective model in a time-reversal (T) symmetric lattice description. We determine the correlated phases of this model and identify a density-wave order in the phase diagram. We show that this order is T-breaking, which originates from the Wannier orbitals lacking a common Wannier center -- a fingerprint of the underlying $Z_2$ topology. Implications of our results for the correlation physics of the kagome metals are discussed.