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arXiv · 2603.09603

On the origin of diverse interlayer charge redistribution in transition-metal dichalcogenides

Yu-Meng Gao·Nie-Wei Wang·Shi-Xuan Yuan·Wen-Xin Xia·Jiang-Long Wang·Xing-Qiang Shi
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Abstract

The interlayer quasi-chemical-bonding (QCB) interactions of two-dimensional (2D) layered materials promote the research field of interlayer-engineering and cause interlayer charge density redistributions (ICDRs). The ICDRs have been reported experimentally and theoretically, which show different redistributions, e.g., accumulation, depletion, or a more complicated behavior. The underlying mechanism for the different ICDRs remain to be elucidated. In the current work, via a systematic theoretical study of the ICDRs of transition metal dichalcogenides with different number of d-electrons filling (d^0 TiS2, d^1 NbS2, and d^2 MoS2) in T and H phases, we reveal three mechanisms based on the coexistence of different types of interlayer QCB interactions. Mechanism (1) is from a competition between two types of interlayer interactions: namely, the interlayer interaction between fully occupied energy levels (in short: o-o interaction) depletes electrons in the overlap region while that between occupied and empty levels (o-e interaction) promotes electron accumulation; and the competition between them leads to that the d^0 TiS2 tends to electron accumulation in T phase than in H phase. Mechanism (2), the interlayer interaction between half-filled levels (h-h interaction) promotes the electron accumulation of d^1 NbS2. Mechanism (3), the interlayer interaction of multiple filled-levels of d^2 MoS2 (namely, the multi-level o-o interaction) leads to a more complicated ICDR. The current study provides a unified understanding to the different ICDRs of van der Waals materials and paves the way for further exploration of their electronic properties and applications.

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Yu-Meng Gao, Nie-Wei Wang, Shi-Xuan Yuan, Wen-Xin Xia, Jiang-Long Wang, Xing-Qiang Shi. 2026-03-10. On the origin of diverse interlayer charge redistribution in transition-metal dichalcogenides. https://arxiv.org/abs/2603.09603

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