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 Al2SbBi, the dynamical, thermal, and mechanical stabilities of which are confirmed by first-principles calculations. Monolayer Al2SbBi 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 Al2SbBi exhibits piezoelectricity and the piezoelectric strain coefficients d11 and d31 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 Al2SbBi has potential applications in spintronic and piezoelectric devices.
@article{arxiv.2305.17995,
title = {Large spin splitting and piezoelectricity in a two-dimensional topological insulator Al$_2$SbBi with double-layer honeycomb structure},
author = {D. Q. Fang and H. Zhang and D. W. Wang},
journal= {arXiv preprint arXiv:2305.17995},
year = {2023}
}