Hydrogenated derivatives of hexacoordinated metallic Cu 2 Si monolayer.

Herein, we carried out first-principles calculations based on density functional theory to investigate the effects of surface functionalization with hydrogen atoms on structural, dynamical and electronic properties of Cu 2 Si monolayer. Pristine Cu 2 Si, a metallic monolayer, has a planar hexacoordinate structure. Calculations revealed that the most favorable position of a single H atom on the Cu 2 Si monolayer is at the top of a Si site. Derivatives of Cu 2 Si monolayer with various H concentrations were investigated, and by performing phonon calculations, it was found that there are three stable hydrogenated structures. Specific heat of these monolayers was found to increase with the hydrogen concentration at temperatures higher than 100 K. Electronically, the hydrogenated derivatives of Cu 2 Si monolayer preserve the metallic character.