Spin liquid in twisted homobilayers of group-VI dichalcogenides,Physical Review B

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Spin liquid in twisted homobilayers of group-VI dichalcogenides
Physical Review B ( IF 3.2 ) Pub Date : 2021-09-24 , DOI: 10.1103/physrevb.104.115154
Mohammad-Hossein Zare ₁ , Hamid Mosadeq ₂

Affiliation

Twisted transition metal dichalcogenide (TMD) homobilayers have recently emerged as a powerful platform for studying correlated insulating states. In the strongly correlated limit, we construct an effective spin Hamiltonian on a honeycomb lattice that includes the Heisenberg interaction and nonsymmetric interactions such as a Dzyaloshinskii-Moriya interaction and a Kane-Mele coupling for the Mott-insulating phase at half-filling. For the twisted TMD homobilayers, the spin-orbit coupling in the Hubbard model, which is expected to induce the antisymmetric exchange couplings in the effective spin Hamiltonian, is a highly tunable and experimentally accessible quantity that can be tuned by an applied electric field. In this study, we investigate classical and quantum phase diagrams of the effective spin Hamiltonian using analytical and numerical methods. We show that the model exhibits a rich classical phase diagram including an antiferromagnetic (AFM) phase, a planar spiral ordered phase with high classical degeneracy, a

z

-AFM phase, a noncoplanar phase, a noncollinear phase, and a

120^{\circ}

-AFM phase. In the quantum treatment, we calculate low-energy magnon excitation spectrum, ground-state energy, and static spin structure factor using linear spin-wave theory and density matrix renormalization group methods to compose the quantum phase diagram of the effective spin Hamiltonian. Beyond the Heisenberg interaction, we find that the existence of these antisymmetric couplings is responsible for the quantum spin liquid,

z

-AFM, noncoplanar, and

120^{\circ}

phases. Twisted TMD homobilayers, therefore, offer rich platforms for realizing rich phases of matter such as quantum spin liquid, noncoplanar, and

120^{\circ}

, resulting from the spin-orbit coupling.

中文翻译：

第 VI 族二硫属化物的扭曲均层中的自旋液体

扭曲的过渡金属二硫属化物 (TMD) homobilayers 最近已成为研究相关绝缘状态的强大平台。在强相关极限中，我们在蜂窝晶格上构建了一个有效的自旋哈密顿量，其中包括海森堡相互作用和非对称相互作用，例如 Dzyaloshinskii-Moriya 相互作用和半填充时莫特绝缘相的 Kane-Mele 耦合。对于扭曲的 TMD homobilayers，哈伯德模型中的自旋轨道耦合预计会在有效自旋哈密顿量中引起反对称交换耦合，这是一个高度可调且实验上可访问的量，可以通过外加电场进行调整。在这项研究中，我们使用解析和数值方法研究了有效自旋哈密顿量的经典和量子相图。我们表明该模型展示了丰富的经典相图，包括反铁磁 (AFM) 相、具有高经典简并性的平面螺旋有序相、