Characterization of the ferroelectric phase transition in monolayer In₂Se₃ grown on bilayer graphene

Ferroelectric transitions in monolayer β–In₂Se₃ grown on bilayer graphene were studied using low energy electron diffraction and scanning tunneling microscopy methods. Violation of the electron dispersion during transitions was studied using angle-resolved photoelectron spectroscopy. In contrast to the bulk case, we observed coexistence of stripe (β^′) and zigzag (α^′ ) phases in the low temperature limit. Experimental results were confirmed by total energy calculations of the corresponded structures that were found using ab initio random structure searching technique. As total energies of antiferroelectric β^′ phase and ferroelectric α^′ phase are almost the same, monolayer In₂Se₃ appears to be promising material for the ferroelectric switching devices.