Topological phases in double layers of bismuthene and antimonene

Abstract

Two-dimensional topological insulators show great promise for spintronic applications. Much attention has been placed on single atomic or molecular layers, such as bismuthene. The selections of such materials are, however, limited. To broaden the base of candidate materials with desirable properties for applications, we report herein an exploration of the physics of double layers of bismuthene and antimonene. The electronic structure of a film depends on the number of layers, and it can be modified by epitaxial strain, by changing the effective spin-orbit coupling strength, and by the manner in which the layers are geometrically stacked. First-principles calculations for the double layers reveal a number of phases, including topological insulators, topological semimetals, Dirac semimetals, trivial semimetals, and trivial insulators. Their phase boundaries and the stability of the phases are investigated. The results illustrate a rich pattern of phases that can be realized by tuning lattice strain and effective spin-orbit coupling.

Topological electronic structure and Rashba effect in Bi thin layers: theoretical predictions and experiments

“…In the same logic, the porous allotrope of a Bi monolayer is denominated as bismuthylene [105]. Electronic structure of free-standing bismuthene has been addressed in [101,104] and that of double layer bismuthene in [106]. Some aspects of single-layer films of the group V elements, the so-called pnictogens, have been reviewed in [139].…”

Few-Layer Bismuthene for Coexistence of Harmonic and Dual Wavelength in a Mode-Locked Fiber Laser

“…In recent decades, ultrathin two-dimensional (2D) nanomaterials have been investigated widely in the fields of electrics, optoelectronics, ultrafast photonics, harmonic generation, energy storage, and biomedical science arising from their extraordinary structure features. − Bismuthene, a kind of novel narrow-band gap (less than 1 eV) nonmagnetic 2D atomic-layered nanomaterial with buckled honeycomb and black-phosphorus-like structures, has depict various outstanding properties such as high carrier mobility, topological phases transition, stability at room temperature, high-temperature quantum spin Hall effect, and nonlinear optical responds, which attracts tremendous interests in theory and experiment. Furthermore, semiconductor bismuthene with direct band gap and semimetal bulk bismuth with indirect band gap could be transformed mutually .…”

Disorder effects of vacancies on the electronic transport properties of realistic topological insulators nanoribbons: the case of bismuthene

“…Among several candidates for topological materials, bismuthene, also known as buckled or bilayer bismuthene, is of special interest due to its large electronic band gap of 0.5 eV, along with its structural stability and large spin-orbit coupling (SOC) [16][17][18]. The existence of charge puddles and other types of defects that could be detrimental for the formation of a topological phase do not play an important role in bismuthene, as experimentally demonstrated [7].…”

“…The robustness of bismuthene non-trivial topology [19] makes it ideal for material design by tuning the lattice constant and effective spin-orbit coupling (SOC) by epitaxial constraint, and lighter elements substitutional alloying with Sb or As, without causing a topological transition [16,21]. The presence of non-magnetic defects leaves the band topology unchanged in these materials [18][19][20].…”