Semiconductor and topological phases in lateral heterostructures constructed from germanene and AsSb monolayers

Two-dimensional (2D) heterostructures have attracted a lot of attention due to their novel properties induced by the synergistic effects of the constituent building blocks. In this work, new lateral heterostructures (LHSs) formed by stitching germanene and AsSb monolayers are investigated. First-principles calculations assert the semimetal and semiconductor characters of 2D germanene and AsSb, respectively. The non-magnetic nature is preserved by forming LHSs along the armchair direction, where the band gap of the germanene monolayer can be increased to 0.87 eV. Meanwhile, magnetism may emerge in the zigzag-interline LHSs depending on the chemical composition. Such that, total magnetic moments up to 0.49 μ_B can be obtained, being produced mainly at the interfaces. The calculated band structures show either topological gap or gapless protected interface states, with quantum spin-valley Hall effects and Weyl semimetal characters. The results introduce new lateral heterostructures with novel electronic and magnetic properties, which can be controlled by the interline formation.