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arXiv · 2607.14951

Self-organized defect clustering and concentration-dependent vacancy diffusion in MoS$_2$

Aaron Flötotto·Benjamin Spetzler·Martin Ziegler·Erich Runge·Christian Dreßler
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Abstract

Sulfur vacancy migration has a crucial impact on electronic transport and the functional behavior of MoS$_2$-based devices such as memristors and memtransistors. According to recent atomistic simulations, vacancy migration proceeds via cooperative, vacancy-assisted sulfur jumps, implying strongly correlated defect dynamics. Here, we investigate the collective behavior of sulfur-vacancy clusters in MoS$_2$ using kinetic Monte-Carlo simulations with transition rates derived from machine learning interatomic potential molecular dynamics simulations. We identify three transport regimes: At low concentrations, vacancies are immobile or confined within small clusters, whereas at high concentrations, classical diffusive transport with a constant diffusion coefficient is observed, and vacancies aggregate into anisotropically extended clusters. A well defined intermediate regime is characterized by clusters merging into a connected, fluctuating network with a concentration-dependent diffusion coefficient. This regime is characterized by a broad distribution of cluster sizes. The strong dependence of the vacancy diffusion coefficient on the average defect concentration provides new insights into the origin of memristive behavior observed in MoS$_2$.

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Aaron Flötotto, Benjamin Spetzler, Martin Ziegler, Erich Runge, Christian Dreßler. 2026-07-16. Self-organized defect clustering and concentration-dependent vacancy diffusion in MoS$_2$. https://arxiv.org/abs/2607.14951

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