Unconventional band inversion and intrinsic quantum spin Hall effect in functionalized group-V binary films

Abstract

Adequately understanding band inversion mechanism, one of the significant representations of topological phase, has substantial implications for design and regulation of topological insulators (TIs). Here, by identifying an unconventional band inversion, we propose an intrinsic quantum spin Hall (QSH) effect in iodinated group-V binary (ABI2) monolayers with a bulk gap as large as 0.409 eV, guaranteeing its viable application at room temperature. The nontrivial topological characters, which can be established by explicit demonstration of Z2 invariant and gapless helical edge states, are derived from the band inversion of antibonding states of p x,y orbitals at the K point. Furthermore, the topological properties are tunable under strain engineering and external electric field, which supplies a route to manipulate the spin/charge conductance of edge states. These findings not only provide a new platform to better understand the underlying origin of QSH effect in functionalized group-V films, but also are highly desirable to design large-gap QSH insulators for practical applications in spintronics.

Electronic Structural and Optical Properties of Multilayer Blue Phosphorus: A First-Principle Study

“…The phonon spectrum is calculated using a supercell approach within the PHONOPY code [30]. From Figure 2, the dynamic stability is confirmed by the phonon spectrum calculated along the highly symmetric directions with zero strain, and the frequencies of all modes are positive over the whole Brillouin zone, indicating the structure is dynamically stable [31][32][33][34][35][36][37][38][39][40].…”

Theoretical studies on tunable electronic structures and potential applications of two‐dimensional arsenene‐based materials

“…Such planarization could induce unique electronic properties. The functionalized arsenene AsR nanosheets, which are terminally decorated with R=H, F, Cl, Br, I, O, OH, CH 3 , etc, have aroused particular interests …”

“…The functionalized arsenene AsR nanosheets, which are terminally decorated with R=H, F, Cl, Br, I, O, OH, CH 3 , etc, have aroused particular interests. [65][66][67][68][69][70][71][72][73][74][75][76][77] The electronic structures of halogenated arsenenes were predicted to be stable via formation energy calculations, except AsI monolayer. The Dirac cone was found to appear in the halogenated arsenenes, 68,69 probably due to flattening of the structures of monolayer arsenenes upon fluorination.…”

“…In addition, various chemical functionalization routes have been proposed to predict the nontrivial topological state in the functionalized arsenene, 65,67,69,70,72,73,75,76 similar as demonstrated for stanene-and germanene-based materials. 8,113,119 The arsenene chemically functionalized with substituent groups R=CH 3 , F, and OH were predicted to be 2D TIs.…”

“…Li et al proposed that the iodinated group‐V binary monolayers (ABI 2 ) possess the bulk bandgap of about 0.409 eV, allowing their real application at room temperature. The nontrivial topological characters were derived from antibonding p x,y orbitals at K point.…”