On the Spontaneous Structural Reconstructions of Chalcogen-Depleted MoS2, MoSe2, and Janus MoSSe Monolayers
Abstract
Removing one chalcogen layer from a transition-metal dichalcogenide monolayer leaves an undercoordinated sheet that reconstructs as the remaining chalcogen atoms cross the metal plane. Here, we combine \textit{ab initio} and reactive molecular dynamics (MD) simulations of depleted MoS2, MoSe2, and Janus MoSSe, examining each remaining chalcogen on two parent lattices, to show that the remaining chalcogen type determines the structural reconstruction, with only a minor influence from the parent lattice. In \textit{ab initio} trajectories of the Janus-derived sheets, Se crosses the Mo plane already at 300~K, whereas S stays in place at 300~K and the sheet reconstructs only at 900~K. With a free in-plane cell, the crossings precede an anisotropic lattice contraction, which therefore results from the structural reconstruction. Reactive MD simulations of 50~nm sheets show that, when S remains, the Mo lattice stays crystalline in nanometric domains that disappear with time and temperature, with pores/holes at 900~K. In contrast, when Se remains, the Mo lattice loses crystalline order within the first picosecond, and 36--39\% of the Se atoms cross at every temperature. In a depleted lateral MoS2/MoSe2 heterostructure, both modes coexist in one sheet, each half reconstructing like its single-chalcogen counterpart, suggesting chalcogen patterning as a route to define crystalline and disordered regions in a single monolayer.
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BibTeX
@misc{ipaves2026spontaneous,
title = {{On the Spontaneous Structural Reconstructions of Chalcogen-Depleted MoS$_2$, MoSe$_2$, and Janus MoSSe Monolayers}},
author = {Bruno Ipaves and Guilherme S. L. Fabris and Raphael B. Oliveira and Pulickel M. Ajayan and Marcelo L. Pereira Junior and Douglas S. Galvão},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.32712},
eprint = {2610.32712},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.32712},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - On the Spontaneous Structural Reconstructions of Chalcogen-Depleted MoS_2, MoSe_2, and Janus MoSSe Monolayers
AU - Bruno Ipaves
AU - Guilherme S. L. Fabris
AU - Raphael B. Oliveira
AU - Pulickel M. Ajayan
AU - Marcelo L. Pereira Junior
AU - Douglas S. Galvão
PY - 2026
DA - 2026/10/23
PB - arXiv
DO - 10.48550/arxiv.2610.32712
UR - https://arxiv.org/abs/2610.32712
AB - Removing one chalcogen layer from a transition-metal dichalcogenide monolayer leaves an undercoordinated sheet that reconstructs as the remaining chalcogen atoms cross the metal plane. Here, we combine \textit{ab initio} and reactive molecular dynamics (MD) simulations of depleted MoS_2, MoSe_2, and Janus MoSSe, examining each remaining chalcogen on two parent lattices, to show that the remaining chalcogen type determines the structural reconstruction, with only a minor influence from the parent lattice. In \textit{ab initio} trajectories of the Janus-derived sheets, Se crosses the Mo plane already at 300~K, whereas S stays in place at 300~K and the sheet reconstructs only at 900~K. With a free in-plane cell, the crossings precede an anisotropic lattice contraction, which therefore results from the structural reconstruction. Reactive MD simulations of 50~nm sheets show that, when S remains, the Mo lattice stays crystalline in nanometric domains that disappear with time and temperature, with pores/holes at 900~K. In contrast, when Se remains, the Mo lattice loses crystalline order within the first picosecond, and 36--39\% of the Se atoms cross at every temperature. In a depleted lateral MoS_2/MoSe_2 heterostructure, both modes coexist in one sheet, each half reconstructing like its single-chalcogen counterpart, suggesting chalcogen patterning as a route to define crystalline and disordered regions in a single monolayer.
ER -