High Bipolar Conductivity and Robust In-Plane Spontaneous Electric Polarization in Selenene

Selenene has been predicted as a new member of an atomically thin 2D crystalline material family as of last year. With first principle calculations, two different stable phases of selenene, one with the 1T-MoS2-like structure (alpha-Se) and the other with alternating arrangement structure of deformed four-membered and six-membered rings (beta-Se) are identified. Further research indicates that monolayer alpha-Se exhibits excellent bipolar conductivity, possessing rather high hole mobility close to that of graphene, and monolayer beta-Se shows a robust in-plane spontaneous electric polarization of 13.46 mu C cm(-2) and a polarization reversing barrier of 422 meV per unit cell. The findings offer a promising material for high speed electronic devices and broaden the family of 2D ferroelectric materials, especially the family of elemental ferroelectric materials.