A metallic CrS${}_2$ phase bridging the gap between two- and three-dimensional dichalcogenides

Abstract

We report on the high-pressure synthesis of a CrS${}_2$ phase in the form of single-crystalline nanorods. A structural refinement of Precession Electron Diffraction Tomography data confirms the nominal CrS${}_2$ composition and unveils a ladder-type structure formed by portions of 1T-type CrS${}_2$ layers characteristic of two-dimensional (2D) dichalcogenides connected by chains of edge-sharing CrS${}_6$ octahedra characteristic of 3D dichalcogenides with marcasite structure. Ab initio density functional theory calculations of the relaxed structure confirm the stability of this structure and indicate a strong overlap of the 3d states of Cr with the 3p states of S, thus suggesting strong covalent Cr-S bonds and metallic behavior. Electrical resistivity, $\varrho$, measurements on single nanorods confirm this behavior and yield $\varrho \sim 2-20$ m$\hat{I}\text{c◯}$ cm at 4 K. The proposed ladder-like structure of CrS${}_2$ forms open channels along the chain direction, which may be suitable for ionic conduction.

25 pages, 5 figures