Spin splitting with persistent spin textures induced by the line defect in the 1T phase of monolayer transition metal dichalcogenides
Spin splitting with persistent spin textures induced by the line defect in the 1T phase of monolayer transition metal dichalcogenides
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DOI：
10.1103/physrevb.101.155410
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发表时间：
2020-01
影响因子：
3.7
通讯作者：
M. Absor;I. Santoso;N. Yamaguchi;F. Ishii
中科院分区：
文献类型：
--
作者：
M. Absor;I. Santoso;N. Yamaguchi;F. Ishii
单层(ML)过渡金属二卤化物(TMDC)家族中的自旋轨道耦合驱动的自旋分裂已被广泛研究，但由于晶体的中心对称性，其$1T相结构尚未得到广泛研究。在第一性原理计算的基础上，我们证明了引入线缺陷可以在ML$1T$-TMDCs中诱导出显著的自旋分裂。以ML${\mathm{PtSe}}_{2}$为例，我们考虑了最稳定的线缺陷形式，即Se空位线缺陷(Se-VLD)。我们发现，在Se-VLD的缺陷态中观察到了大的自旋分裂，在动量空间中表现出高度单向的自旋组态。这种特殊的自旋构型可能会产生所谓的持久自旋织构(PSTs)，这是一种特殊的自旋结构，可以防止自旋退相干，并支持超长的自旋寿命。此外，利用$\stackrel{P\vec}{k}\ifmmode\cdot\else\textperiodcentered\fi{}\stackrel{P\vec}{p}$微扰理论并辅之以对称性分析，我们阐明了维持缺陷态PSTs的自旋分裂的产生源于反转对称性的破坏和Se-VLD工程ML${\mathm{PtSe}}{2}$的一维性质。我们的发现为在ML$1T$-TMDCs中诱导显著的自旋分裂铺平了可能的途径，这对于设计自旋电子器件可能是非常重要的。
The spin splitting driven by spin-orbit coupling in the monolayer (ML) transition metal dichalcogenide (TMDC) family has been widely studied only for the $1H$-phase structure, while its $1T$-phase structure has not been as widely researched due to the centrosymmetry of the crystal. Based on first-principles calculations, we show that significant spin splitting can be induced in the ML $1T$-TMDCs by introducing the line defect. Taking the ML ${\mathrm{PtSe}}_{2}$ as a representative example, we considered the stablest form of the line defects, namely, the Se vacancy line defect (Se-VLD). We find that large spin splitting is observed in the defect states of the Se-VLD, exhibiting a highly unidirectional spin configuration in the momentum space. This peculiar spin configuration may yield the so-called persistent spin textures (PSTs), a specific spin structure resulting in protection against spin decoherence and supporting an extraordinarily long spin lifetime. Moreover, by using $\stackrel{P\vec}{k}\ifmmode\cdot\else\textperiodcentered\fi{}\stackrel{P\vec}{p}$ perturbation theory supplemented with symmetry analysis, we clarified that the emerging of the spin splitting maintaining the PSTs in the defect states originates from the inversion symmetry breaking together with the one-dimensional nature of the Se-VLD engineered ML ${\mathrm{PtSe}}_{2}$. Our findings pave a possible way to induce significant spin splitting in the ML $1T$-TMDCs, which could be highly important for designing spintronic devices.