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arXiv 2110.00536cond-mat.str-el
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扭曲同双层中的自旋液体VI族硫属元素

Spin liquid in twisted homobilayers group-VI gichalcogenides

Mohammad-Hossein Zare, Hamid Mosadeq

摘要:

扭曲过渡金属二硫属化物(TMD)同质双层膜最近成为研究相关绝缘态的一个强有力的平台。在强关联极限下,我们构造了一个包含海森堡相互作用和非对称相互作用(如Dzyaloshinskiii-Moriya相互作用和半填充时Mott绝缘相的Kane-Mele耦合)的蜂窝晶格上的有效自旋哈密顿量.对于扭曲TMD同双层,哈伯德模型中的自旋轨道耦合是一个高度可调的实验可达量,可以通过外加电场来调节,它被认为是有效自旋哈密顿量中的反对称交换耦合.在这项研究中,我们使用分析和数值方法研究了有效自旋汉密尔顿的经典和量子相图。我们表明,该模型具有丰富的经典相图,包括反铁磁(AFM)相,具有高经典简并的平面螺旋有序相,$z$ -AFM相,非共面相,非共线相,和120 $^{\circ}$ -AFM相。在量子化处理中,我们利用线性自旋波理论和密度矩阵重整化群方法计算了低能磁振子激发谱、基态能量和静态自旋结构因子,从而组成了有效自旋哈密顿量的量子相图。除了海森堡相互作用,我们发现,这些反对称耦合的存在是负责量子自旋液体,$z$ -AFM,非共面,和120 $^{\circ}$相。因此,扭曲TMD同双层膜为实现物质的丰富相态提供了丰富的平台,如量子自旋液体,非共面和120 $^{\circ}$,由自旋轨道耦合产生。

英文摘要:

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.

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