Screening transition metal-based polar pentagonal monolayers with large piezoelectricity and shift current

• Published in: npj computational materials Vol. 8; no. 1; pp. 1 - 9
• Main Authors: Guo, Yaguang, Zhou, Jian, Xie, Huanhuan, Chen, Yanyan, Wang, Qian
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.03.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/119; 639/301/357; Characterization and Evaluation of Materials; Chemistry and Materials Science; Computational Intelligence; Electric polarization; Ferroelectric materials; Ferroelectricity; First principles; High-throughput screening; Materials Science; Mathematical and Computational Engineering; Mathematical and Computational Physics; Mathematical Modeling and Industrial Mathematics; Metal compounds; Monolayers; Phase transitions; Piezoelectricity; Screening; Theoretical; Transition metal compounds; Two dimensional materials
• ISSN: 2057-3960; 2057-3960
• DOI: 10.1038/s41524-022-00728-4

Two-dimensional (2D) materials entirely composed of pentagon motifs are of interest for their wide applications. Here, we demonstrate that in-plane polar symmetry can exist in ternary pentagonal monolayers, where the induced electric polarization is not associated with specific conditions, such as ferroelectric phase transition, strain gradient, and layer stacking, but is an intrinsic structural property coming from the orderly arranged polar bonds. Based on the high-throughput screening method and first-principles calculations, we find eight stable 2D polar transition metal compounds with a number of intriguing properties. In particular, their piezoelectric coefficients are three orders of magnitude larger than those of 2D elemental and binary pentagonal structures, and their bulk photovaltaic shift current can reach up to 300 μA V −2 , superior to that of 2D conventional ferroelectric materials such as GeS. Our identified pentagonal monolayers not only expand the family of 2D pyroelectric materials, but also hold potential for energy conversions.