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Nano Research

Article Title

Scanning tunneling spectroscopic study of monolayer 1T-TaS2 and 1T-TaSe2

Keywords

monolayer, 1T-TaS2, 1T-TaSe2, commensurate charge density wave (CCDW), Mott gap, band insulator

Abstract

The isostructural and isoelectronic transition-metal-dichalcogenides 1T-TaS2 and 1T-TaSe2 are layered materials with intricate electronic structures. Combining the molecular beam epitaxy growth, scanning tunneling microscopy measurements and firstprinciples calculations, we prepare monolayer 1T-TaS2 and TaSe2 and explore their electronic structures at the atomic scale. Both two-dimensional (2D) compounds exhibit commensurate charge density wave phase at low temperature. The conductance mapping identifies the contributions from different Ta atoms to the local density of states with spatial and energy resolution. Both 1T-TaS2 and 1T-TaSe2 monolayer are shown to be insulators, while the former has a Mott gap and the latter is a regular band insulator.

Graphical Abstract

Publisher

Tsinghua University Press

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