The electronic structure and phonon dispersion of XS2 with X = Co, Tc, Ti, Ru, Nb, and Rh in the monolayer MoS2 structure with trigonal-prismatic coordination are studied from first principles. Although each XS2 is dynamically unstable, CoS2, TcS2, RuS2, and RhS2 can be stabilized by developing charge density waves in the (2×2) supercell, leading to metal-insulator transitions. Without really needing the metal-insulator transitions and large atomic distortions, additional energy may be gained in the total energy by mixing transition metal elements to create high-entropy combinations for X, presenting a wide range of high-entropy XS2 compounds that exhibit a variety of band structures, including direct- and indirect-gap semiconductors, metals, and semimetals.
@article{arxiv.2407.00880,
title = {Stabilizing charge density wave by mixing transition metal elements in monolayer XS$_2$ with trigonal-prismatic coordination},
author = {Chi-Cheng Lee and Yukiko Yamada-Takamura},
journal= {arXiv preprint arXiv:2407.00880},
year = {2025}
}