ABSTRACT
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 µB 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.
ABSTRACT
Seamlessly stitching two-dimensional (2D) materials may lead to the emergence of novel properties triggered by the interactions at the interface. In this work, a series of 2D lateral heterostructures (LHSs), namely germanene-arsenene (Gem-As8-m) and germanene-antimonene (Gem-Sb8-m), are investigated using first-principles calculations. The results demonstrate a strong interline-dependence of the electronic and magnetic properties. Specifically, the LHS formation along an armchair line preserves the non-magnetic nature of the original materials. However, this is an efficient approach to open the electronic band gap of the germanene monolayer, where band gaps as large as 0.74 and 0.76 eV are induced for Ge2-As6 and Ge2-Sb6 LHSs, respectively. Meanwhile, magnetism may appear in the zigzag-LHSs depending on the chemical composition (m = 3, 4, 5, and 6 for germanene-arsenene and m = 2, 3, 4, 5, and 6 for germanene-antimonene), where total magnetic moments between 0.13 and 0.50 µB are obtained. Herein, magnetic properties are produced mainly by the spin-up state of Ge atoms at the interface, where a small contribution comes from As(Sb) atoms. Spin-resolved band structures show a multivalley profile in both the valence band and the conduction band with a topological insulator-like behavior, where the interface states are derived mainly from the interface Ge-pz state. The results introduce new 2D lateral heterostructures with novel electronic and magnetic properties to allow new functionalities, which could be further explored for optoelectronic and spintronic applications.
