Band structure, ferroelectric instability, and spin–orbital coupling effect of bilayer α-In2Se3
| Autor: | S. H. Zheng, J.-M. Liu, Chun-zao Li, L. Lin, Yifeng Li, Y. Zhang, X. P. Jiang, Y. S. Tang, Jibiao Zhang, Zhendong Yan |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Physics Condensed matter physics Band gap Bilayer General Physics and Astronomy 02 engineering and technology Spin–orbit interaction 021001 nanoscience & nanotechnology 01 natural sciences Ferroelectricity Instability symbols.namesake 0103 physical sciences symbols van der Waals force 0210 nano-technology Electronic band structure Ground state |
| Zdroj: | Journal of Applied Physics. 128:234106 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/5.0029646 |
| Popis: | Recently, two-dimensional van der Waals ferroelectrics have been receiving much interest with continuous exploration of the underlying physics and device applications. While α-In2Se3 in an atomically thin crystal form is believed to have nonzero out-of-plane polarization, its ferroelectric (FE) instability in competition with the antiferroelectric (AFE) ground state is highly concerned. Along this line, a bilayer α-In2Se3 structure should be a good object for clarifying this issue since it is the simplest 2D lattice accommodating an AFE state, possibly allowing the AFE–FE competition. In this work, we employ the first-principles calculation to investigate the lattice and electronic structures of bilayer α-In2Se3, and special attention is paid to the FE instability in competition with the AFE ground state. It is found that the energy difference between the AFE ground state and FE state is small, thereby allowing an electric field modulation of the AFE–FE inter-conversion. More importantly, the Hyed–Scuseria–Ernzerhof algorithm predicts that the FE state is indeed semiconducting rather than metallic, removing the inconsistency between experimental observation and theoretical prediction. The spin–orbital coupling effect can further enlarge the bandgap and drive the indirect-to-direct bandgap transition, and thus appears to be an important ingredient of the underlying physics. |
| Databáze: | OpenAIRE |
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