Adsorption Tuning of Polarity and Magnetism in AgCr(2)S(4) Monolayer

As a recent successfully exfoliated non-van der Waals layered material, AgCrS(2) has received a lot of attention. Motivated by its structure-related magnetic and ferroelectric behavior, a theoretical study on its exfoliated monolayer AgCr(2)S(4) has been carried out in the present work. Based on density functional theory, the ground state and magnetic order of monolayer AgCr(2)S(4) have been determined. The centrosymmetry emerges upon two-dimensional confinement and thus eliminates the bulk polarity. Moreover, two-dimensional ferromagnetism appears in the CrS(2) layer of AgCr(2)S(4) and can persist up to room temperature. The surface adsorption has also been taken into consideration, which shows a nonmonotonic effect on the ionic conductivity through ion displacement of the interlayer Ag, but has little impact on the layered magnetic structure.