Large spin splitting and piezoelectricity in a two-dimensional topological insulator Al$_2$SbBi with double-layer honeycomb structure

D. Q. Fang; H. Zhang; D. W. Wang

doi:10.1021/acsanm.3c02786

paper

Large spin splitting and piezoelectricity in a two-dimensional topological insulator Al $_{2}$ SbBi with double-layer honeycomb structure

arXiv:2305.17995 · doi:10.1021/acsanm.3c02786

Abstract

Two-dimensional materials provide remarkable platforms to uncover intriguing quantum phenomena and develop nanoscale devices of versatile applications. Recently, AlSb in the double-layer honeycomb (DLHC) structure was successfully synthesized exhibiting a semiconducting nature [ACS Nano 15, 8184 (2021)], which corroborates the preceding theoretical predictions and stimulates the exploration of new robust DLHC materials. In this work, we propose a Janus DLHC monolayer Al $_{2}$ SbBi, the dynamical, thermal, and mechanical stabilities of which are confirmed by first-principles calculations. Monolayer Al $_{2}$ SbBi is found to be a nontrivial topological insulator with a gap of about 0.2 eV, which presents large spin splitting and peculiar spin texture in the valence bands. Furthermore, due to the absence of inversion symmetry, monolayer Al $_{2}$ SbBi exhibits piezoelectricity and the piezoelectric strain coefficients d $_{11}$ and d $_{31}$ are calculated to be 7.97 pm/V and 0.33 pm/V, respectively, which are comparable to and even larger than those of many piezoelectric materials. Our study suggests that monolayer Al $_{2}$ SbBi has potential applications in spintronic and piezoelectric devices.

Large spin splitting and piezoelectricity in a two-dimensional topological insulator Al2​SbBi with double-layer honeycomb structure

Abstract

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Large spin splitting and piezoelectricity in a two-dimensional topological insulator Al $_{2}$ SbBi with double-layer honeycomb structure