Theoretical design of a new family of two-dimensional topological insulators

Abstract

A new family of two-dimensional topological insulator, hydrogenated monolayer Pb₂XY (X = Ga/In, Y = Sb/Bi), has been predicted using first-principles density functional theory. The electronic bulk band gap of the proposed systems can be induced in the presence of a spin–orbit coupling effect and its highest value (0.25 eV) was observed in the hydrogenated monolayer Pb₂GaBi, which is suitable for practical application. Our simulation study points out that the nanoribbons derived from this new family harbor gapless edge channels. The non-trivial topological nature was further confirmed by calculating the Z₂ topological invariant. These novel systems provide a new platform for topological phenomena observation and spintronic applications.