Tunable Single-Atomic Charges on a Cleaved Intercalated Transition Metal Dichalcogenide.

Lim, Seongjoon; Pan, Shangke; Wang, Kefeng; Ushakov, Alexey V; Sukhanova, Ekaterina V; Popov, Zakhar I; Kvashnin, Dmitry G; Streltsov, Sergey V et al. · Nano Lett · 2022

basic_science · Level V

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Abstract

Control of a single ionic charge state by altering the number of bound electrons has been considered as an ultimate testbed for atomic charge-induced interactions and manipulations, and such subject has been studied in artificially deposited objects on thin insulating layers. We demonstrate that an entire layer of controllable atomic charges on a periodic lattice can be obtained by cleaving metallic Co<sub>1/3</sub>NbS<sub>2</sub>, an intercalated transition metal dichalcogenide. We identified a metastable charge state of Co with a different valence and manipulated atomic charges to form a linear chain of the metastable charge state. Density functional theory investigation reveals that the charge state is stable due to a modified crystal field at the surface despite the coupling between NbS<sub>2</sub> and Co via a<sub>1g</sub> orbitals. The idea can be generalized to other combinations of intercalants and base matrices, suggesting that they can be a new platform to explore single-atom-operational 2D electronics/spintronics.