Topological electronic states, superconductivity, and ferromagnetism in two-dimensional ScXS2 (X=Rh, Ta, Mo) monolayers

Abstract

The two-dimensional (2D) materials with coexistence of Dirac points and Van Hove singularities (VHSs) provide a promising platform for seeking topological superconductivity or ferromagnetism at high critical temperatures. However, ideal examples combining electronic topological properties with superconductivity or ferromagnetism are scarce. Here, through structural search, we identify 2D ScXS2 (X = Rh, Ta, Mo) monolayers with simple square or rectangular lattices, where VHSs lie near Dirac points close to the Fermi levels. Using first-principles calculations, Bardeen-Cooper-Schrieffer theory, and Monte Carlo simulations, we found that all the three monolayers exhibit nontrivial topological electronic properties. Moreover, ScRhS2 is intrinsically superconducting with Tc = 1.36 K; ScTaS2 shows tunable superconductivity reaching Tc = 2.21 K under 6% uniaxial tensile strain which also displays ferroelasticity induced by the Jahn-Teller effect; and ScMoS2 hosts a topological ferromagnetic half-metal ground state with a giant anomalous Hall effect and Curie temperature of 329 K stabilized by a high magnetic anisotropy energy of 1.837 meV/Mo. These results establish ScXS2 monolayers as a versatile 2D material family for exploring exotic mixtures of topological states, superconductivity, and half-metal ferromagnetism, offering potential for novel electronic and spintronic applications.

Source-reported materials — not catalogue approval

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