First-principles study of two-dimensional ferroelectrics using self-consistent Hubbard parameters

Article

关键词: ELECTRONIC-STRUCTURE;    APPROXIMATION;    INPLANE;    SPECTRA;    OXIDE;    NI;   

DOI  :  10.1103/PhysRevB.102.165157

来源: SCIE

【 摘 要 】

The discovery of two-dimensional (2D) materials possessing switchable spontaneous polarization with atomic thickness opens up exciting opportunities to realize ultrathin, high-density electronic devices with potential applications ranging from memories and sensors to photocatalysis and solar cells. First-principles methods based on density functional theory (DFT) have facilitated the discovery and design of 2D ferroelectrics (FEs). However, DFT calculations employing local and semilocal exchange-correlation functionals failed to predict accurately the band gaps for this family of low dimensional materials. Here, we present a DFT + U + V study on 2D FEs represented by alpha-In2Se3 and its homologous III2-VI3 compounds with both out-of-plane and in-plane polarization, using Hubbard parameters computed from first principles. We find that ACBNO, a pseudohybrid density functional that allows self-consistent determination of U parameters, improves the prediction of band gaps for all investigated 2D FEs with a computational cost much lower than the Heyd-Scuseria-Ernzerhof hybrid density functional. The intersite Coulomb interaction V becomes critical for accurate descriptions of the electronic structures of van der Waals heterostructures such as bilayer In2Se3 and In2Se3/InTe. Pertinent to the study of FE-based catalysis, we find that the application of self-consistent U corrections can strongly affect the adsorption energies of open-shell molecules on the polar surfaces of 2D FEs.

【 授权许可】

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