Topological Phases in Hydrogenated Group 13 Monolayers

The topological phases of matters have been a rapid exposed field of research due to its possible applications in spintronics and fault-tolerant quantum computing. Recently, the 2D sheet of gallium (gallenene), a group 13 element, has been synthesized, for which topological properties remain undefined. Using an effective k.p model, symmetry analysis and group theoretical approach with first-principles calculations we studied the topological properties of hydrogenated gallenene (gallenane) and other group 13 elements. Without the inclusion of spin-orbit coupling (SOC) all hydrogenated group-13 sheets that are aluminane, gallenane, indinane and thallinane become nodal line semimetal (NLSM). Interestingly, gallenane under SOC and with 2.6% tensile strain evolves to quantum spin Hall insulator with an energy gap of 28 meV, which makes it promising for room temperature applications. Aluminane preserved its topology even in the presence of SOC due to feeble strength of it. Indinane and thallinane are trivial semimetals under SOC. These findings could offer a new direction in topological research.

J. Phys. Chem. C, 2019, 12342, 25985-25990