Quantum spin Hall effect in two-dimensional transition-metal dichalcogenide haeckelites

This works brings us a step closer towards the realization of the quantum spin Hall (QSH) effect. Using electronic structure calculations, the authors suggest that a family of the single-layer 2D transition metal dichalcogenide haeckelites M00exX₂ (M=W or Mo, X=S, Se, or Te) can host the QSH effect at high temperatures. Their work also implies that a square-lattice 2D material can host a nontrivial topological state, thus, extending the search boundaries for topological materials beyond the ones with a hexagonal lattice.