Large spin splitting in the conduction band of transition metal dichalcogenide monolayers
Large spin splitting in the conduction band of transition metal dichalcogenide monolayers
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DOI：
10.1103/physrevb.88.245436
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发表时间：
2013-12-23
影响因子：
3.7
通讯作者：
Fernandez-Rossier, J.
中科院分区：
文献类型：
--
作者：
Kosmider, K.;Gonzalez, J. W.;Fernandez-Rossier, J.
我们研究了由于自旋-轨道耦合和缺乏反转对称性的结合，在过渡金属二硫属化物（TMD）半导体单层，如MoS 2，MoSe 2，WS 2和WSe 2中出现的导带自旋分裂。进行了两种类型的计算。首先，密度泛函理论（DFT）计算的基础上产生大分裂，3和30毫电子伏之间的平面波。其次，我们推导出一个紧束缚模型，允许解决原子的起源分裂。该模型的基组由DFT计算得到的最大局域Wannier轨道提供，并由11个类原子轨道形成，分别对应于过渡金属（W，Mo）和硫属化物（S，Se）原子的d和p轨道。在所得到的哈密顿量中，我们可以独立地改变两个原子物种在单位晶胞处的原子自旋-轨道耦合常数，这允许分析它们对高对称点处的自旋分裂的贡献。我们发现，在对比的价带，两个原子给导带分裂的贡献相当。考虑到这些材料通常是n掺杂的，我们的研究结果对TMD自旋电子学的发展很重要。
We study the conduction band spin splitting that arises in transitionmetal dichalcogenide (TMD) semiconductor monolayers such as MoS2, MoSe2, WS2, and WSe2 due to the combination of spin-orbit coupling and lack of inversion symmetry. Two types of calculation are done. First, density functional theory (DFT) calculations based on plane waves that yield large splittings, between 3 and 30 meV. Second, we derive a tight-binding model that permits to address the atomic origin of the splitting. The basis set of the model is provided by the maximally localized Wannier orbitals, obtained from the DFT calculation, and formed by 11 atomiclike orbitals corresponding to d and p orbitals of the transition metal (W, Mo) and chalcogenide (S, Se) atoms respectively. In the resulting Hamiltonian, we can independently change the atomic spin-orbit coupling constant of the two atomic species at the unit cell, which permits to analyze their contribution to the spin splitting at the high symmetry points. We find that-in contrast to the valence band-both atoms give comparable contributions to the conduction band splittings. Given that these materials are most often n-doped, our findings are important for developments in TMD spintronics.