Theoretical investigations on the stability and electronic structures of two-dimensional group-IV ternary alloy monolayers

Abstract

The structural stability and electronic properties of group-IV ternary alloy monolayers are systematically investigated by using electronic structure calculations based on the density functional theory. Our calculations demonstrate that the buckled configuration is stabilized over a wide composition range with the exception of carbon-incorporated monolayers. The calculated excess energy is found to be comparable to that of the bulk phase, indicating that the miscibility of ternary alloy monolayers is similar to that of the bulk phase. The analysis of band structures also reveals that an almost linear band dispersion with a Dirac cone at the K point (similar to graphene) appears in the SixGeySn1−x−y monolayer, while an energy gap is formed in other monolayers. These results suggest that the ability to control composition is important for tailoring the electronic properties of group-IV ternary alloy monolayers.