发表机构
BITS Pilani, Dubai Campus（印度理工学院比拉尼校区迪拜分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过将量子谷偏转张量嵌入宏观输运模型，揭示应变诱导谷排序效应在MoS₂晶体管中主要由金属接触界面决定，而非体区，并提出了谷拓扑接触电阻及逆长度标度律，为二维材料谷电子学器件设计提供指导。
AI 中文摘要
应变工程是控制单层过渡金属二硫属化物中谷选择性输运的主要途径。这一量子效应能否在完全接触的器件中存续仍是一个悬而未决的问题。量子输运模型能够捕捉潜在的谷偏转，但仅限于孤立的纳米尺度片段，尚不清楚完整器件是否在体区、接触区或任何位置记录应变诱导的谷排序。在此，我们将应变单层MoS$_2$的量子谷偏转张量直接嵌入宏观泊松-漂移-扩散模型中，将该物理机制扩展到包含接触的完整器件。将该框架应用于300~nm单层MoS$_2$晶体管，其具有3~nm HfO$_2$栅介质，在77~K下，在局部6.14~T赝磁场应变场作用下，结果表明所导致的63.6%的导通态电流抑制并非体区属性，而几乎完全由源极和漏极金属-半导体界面决定。当仅对15~nm接触区施加应变时，完全抑制得以重现；而当仅对沟道内部施加应变时，抑制几乎消失，这表明金属接触是应变诱导谷物理效应的主导位置。观测该效应需要隧穿透明的重掺杂接触，因为经典欧姆接触势垒会掩盖拓扑信号。传输线分析将该行为归结为单一的谷拓扑接触电阻（$R_{c,V}$）以及一个预测性的逆长度标度律。该框架适用于任何应变工程的二维材料异质结构，并可通过标准多长度接触结构进行测试。最终，这些结果确定了金属-半导体界面是工程和探测真实二维材料器件中谷选择性输运的决定性位置。
英文摘要
Strain engineering is a leading route to control valley-selective transport in monolayer transition metal dichalcogenides. Whether this quantum effect survives inside a fully contacted device remains an open question. Quantum transport models capture the underlying valley deflection but are limited to isolated nanoscale fragments, leaving it unclear if a full device registers strain-induced valley sorting in the bulk, at the contacts, or at all. Here, the quantum valley-deflection tensor of strained monolayer MoS$_2$ is embedded directly into a macroscopic Poisson-drift-diffusion model, extending this physics to a complete, contact-inclusive device. Applying this framework to a 300~nm monolayer MoS$_2$ transistor with a 3~nm HfO$_2$ gate dielectric at 77~K, under a localized 6.14~T pseudo-magnetic strain field, shows the resulting 63.6\% suppression of the ON-state current is not a bulk property. It is set almost entirely by the source and drain metal-semiconductor interfaces. The full suppression is reproduced when only the 15~nm contact regions are strained and nearly vanishes when the channel interior alone is strained, identifying the metal contact as the dominant site of strain-induced valley physics. Observing it requires tunneling-transparent, degenerately-doped contacts, since classical Ohmic barriers overwhelm the topological signal. A transmission-line analysis reduces this behavior to a single valley-topological contact resistance ($R_{c,V}$) and a predictive inverse-length scaling law. This framework applies to any strain-engineered 2D-material heterostructure and can be tested with standard multi-length contact structures. Ultimately, these results identify the metal-semiconductor interface as the decisive location for engineering and detecting valley-selective transport in real 2D-material devices.
Comments17 pages, 7 figures, 3 tables. Custom SILVACO TCAD scripts, COMSOL files and datasets are all available at https://doi.org/10.5281/zenodo.21346193
