上海科技大学知识管理系统

Microscopically revealing the interactions between interfacial water and the quantum states of matter is an important task from both the materials science and the physics points of view. Here we report a low-temperature scanning tunneling microscopy (STM) and spectroscopy study of water adsorption on the charge density wave compound 1T-TaS2, which has a Mott-insulating ground state. Interfacial water forms monolayer islands with 6 x 6 superstructures on the surface of 1T-TaS2, and the charge order under water islands can be directly imaged in STM topographies taken with negative bias voltages. Compared with the original root 13 x root 13 charge order in 1T-TaS2, the charge order under water islands becomes significantly disordered and denser. A V-shaped gaplike feature emerges in water-covered 1T-TaS2, which may be due to the enhanced dielectric constant of interfacial water, which reduces short-range Coulomb repulsion and induces Mott gap collapse. Our observations open the way to microscopically understanding the interactions between interfacial water and the correlated quantum states of matter.