Self-organized defect clustering and concentration-dependent vacancy diffusion in MoS$_2$
Abstract
Sulfur vacancy migration has a crucial impact on electronic transport and the functional behavior of MoS-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 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.
Cite
@article{arxiv.2607.14951,
title = {Self-organized defect clustering and concentration-dependent vacancy diffusion in MoS$_2$},
author = {Aaron Flötotto and Benjamin Spetzler and Martin Ziegler and Erich Runge and Christian Dreßler},
journal= {arXiv preprint arXiv:2607.14951},
year = {2026}
}