论文标题
带有RASHBA型反对称自旋轨耦合的方格Hubbard模型的相图
Phase diagram of the square lattice Hubbard model with Rashba-type antisymmetric spin-orbit coupling
论文作者
论文摘要
我们用Rashba旋转轨道耦合（SOC）阐明了半填充的方形哈伯德模型的基态相图，其特征是由于反转对称性破裂而引起的自旋分解能带。尽管已经对RashBA金属和绝缘磁体进行了很好的研究，但由于缺乏适当的理论工具来无偏描述大型磁性结构，因此系统的中间相互作用强度仍然难以捉摸。我们补充了四种不同的方法；正弦正方形变形的平均场理论，随机相位近似，Luttinger-Tisza方法和密度矩阵嵌入理论，并成功地捕获了以前被忽略的很长的空间时期，并成功捕获了不相称的自旋密度波（SDW）阶段。从金属相到SDW相的过渡是由前所未有的不稳定性驱动的，该不稳定嵌套了携带相反旋转的费米表面的两个部分。对于大型SOC，当四个狄拉克点在费米级别附近存在，并且它们的整个线性分散体嵌套在波长$π$的情况下，就可以获得螺旋，齿状和涡流阶段。这两种类型的过渡提供了区分反对称SOC系统的Fermiology，从而产生了从相对较弱的相关性制度开始的各种磁相，并继续达到强烈相互作用的极限。
We clarify the ground state phase diagram of the half-filled square-lattice Hubbard model with Rashba spin-orbit coupling (SOC) characterized by the spin-split energy bands due to broken inversion symmetry. Although the Rashba metals and insulating magnets have been studied well, the intermediate interaction strength of the system remained elusive due to the lack of appropriate theoretical tools to unbiasedly describe the large-scale magnetic structures. We complementarily apply four different methods; sine square deformed mean-field theory, random phase approximation, Luttinger-Tisza method, and density matrix embedding theory, and succeed in capturing the incommensurate spin density-wave (SDW) phases with very long spatial periods which were previously overlooked. The transition to the SDW phases from the metallic phase is driven by an unprecedented instability that nests the two parts of the Fermi surface carrying opposite spins. For large SOC, the spiral, stipe, and vortex phases are obtained, when the four Dirac points exist near the Fermi level and their whole linear dispersions nest by a wavelength $π$, opening a band gap. These two types of transition provide Fermiology that distinguishes the antisymmetric SOC systems, generating a variety of magnetic phases that start from the relatively weak correlation regime and continue to the strongly interacting limit.
