Emergent spin-valley-orbital physics by spontaneous parity breaking
Emergent spin-valley-orbital physics by spontaneous parity breaking
复制标题
DOI：
10.1088/0953-8984/28/39/395601
复制
发表时间：
2016-07
期刊：
影响因子：
--
通讯作者：
S. Hayami;H. Kusunose;Y. Motome
中科院分区：
文献类型：
--
作者：
S. Hayami;H. Kusunose;Y. Motome
在没有空间反演对称性的情况下，自旋轨道耦合在实现固体中有趣的电子态（如拓扑绝缘体和非常规超导）中起着重要作用。通常，反演对称性破缺是晶格结构固有的，因此，不容易通过外部参数来控制这些有趣的性质。本文从理论上探讨了由电子相关引起的自发电子有序产生自旋轨道纠缠的可能性。我们特别关注在晶格位置具有局部不对称的中心对称晶格，例如锯齿形结构、蜂窝结构和菱形结构。在这种系统中，常规的交错序，如电荷序和反铁磁序，打破了反转对称性，激活了反对称的自旋轨道耦合，这种耦合在顺磁状态下以亚晶格依赖的形式隐藏。考虑蜂窝结构上的最小双轨道模型，我们仔细研究了所有可能的交错电荷、自旋、轨道和自旋-轨道顺序的反对称自旋-轨道耦合的显式形式。我们表明，完整的表有助于理解自旋-谷-轨道物理，例如电子能带结构中的自旋和谷分裂，以及自旋和轨道和自旋-轨道通道中的广义磁电响应，反映了固体中特殊的磁性，弹性和光学性质。
The spin–orbit coupling in the absence of spatial inversion symmetry plays an important role in realizing intriguing electronic states in solids, such as topological insulators and unconventional superconductivity. Usually, the inversion symmetry breaking is inherent in the lattice structures, and hence, it is not easy to control these interesting properties by external parameters. We here theoretically investigate the possibility of generating the spin-orbital entanglement by spontaneous electronic ordering caused by electron correlations. In particular, we focus on the centrosymmetric lattices with local asymmetry at the lattice sites, e.g. zigzag, honeycomb, and diamond structures. In such systems, conventional staggered orders, such as charge order and antiferromagnetic order, break the inversion symmetry and activate the antisymmetric spin–orbit coupling, which is hidden in a sublattice-dependent form in the paramagnetic state. Considering a minimal two-orbital model on a honeycomb structure, we scrutinize the explicit form of the antisymmetric spin–orbit coupling for all the possible staggered charge, spin, orbital, and spin-orbital orders. We show that the complete table is useful for understanding of spin-valley-orbital physics, such as spin and valley splitting in the electronic band structure and generalized magnetoelectric responses in not only spin but also orbital and spin-orbital channels, reflecting in peculiar magnetic, elastic, and optical properties in solids.