What Dictates Rashba Splitting in 2D van der Waals Heterobilayers,Journal of the American Chemical Society

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What Dictates Rashba Splitting in 2D van der Waals Heterobilayers
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2021-02-24 , DOI: 10.1021/jacs.0c12809
Sunny Gupta ₁ , Boris I. Yakobson _{1,

2,

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Affiliation

Rashba spin–orbit coupling enables electric control of spin states, promising enormous advances from conventional charge-based computing. Until now, a general scheme or a descriptor to find an optimal system with isolated spin states with large tunable splitting is still lacking. Here, based on first-principles calculations, we explore the microscopic physicochemical mechanism responsible for the Rashba effect in 2D van der Waals heterobilayers. We find that the difference in the Born effective charge of atoms at the interface can be used as a single-layer descriptor to predict heteropairs with large Rashba splitting, thus reducing the scaling factor in materials search. Moreover, we discover that for most 2D materials, the routinely used Rashba parameter α_R is not a good gauge of the effect’s strength. From our general scheme, MoTe₂|Tl₂O and MoTe₂|PtS₂, with spin splitting above 120 meV, Rashba energy E_R = 94 meV, and wavenumber difference 2k₀ = 0.36 Å^–1 (“effective” α_R > 1 eVÅ), emerge as the best candidates for spin transistors at room temperature.

中文翻译：

是什么决定了Rashba在2D van der Waals异质双分子层中的分裂

Rashba自旋-轨道耦合实现了对自旋态的电控制，有望实现传统基于电荷的计算的巨大进步。到目前为止，仍然缺乏找到具有大的可调分裂的孤立自旋状态的最优系统的通用方案或描述符。在这里，基于第一性原理的计算，我们探索了在2D van der Waals异质双分子层中引起Rashba效应的微观物理化学机制。我们发现界面处的原子Born有效电荷的差异可以用作单层描述符，以预测具有大Rashba分裂的异质对，从而减少材料搜索中的比例因子。此外，我们发现，对于大多数2D材料中，经常使用的Rashba参数α _{- [R}不能很好地衡量效果的强度。从我们的一般方案，微尘₂ |铊₂ O和微尘₂ | PTS ₂，具有自旋分裂高于120兆电子伏，拉什巴能量ë _[R = 94毫电子伏特，而波数差2 ķ ₀ = 0.36埃^-1（“有效”α _{- [R} > 1eVÅ），成为室温下自旋晶体管的最佳候选者。

更新日期：2021-03-10

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