title: New Ferroelectric Phase in Atomic-Thick Phosphorene Nanoribbons: Existence of in-Plane Electric Polarization.
abstract: Ferroelectrics have many significant applications in electric devices, such as capacitor or random-access memory, tuning the efficiency of solar cell. Although atomic-thick ferroelectrics are the necessary components for high-density electric devices or nanoscale devices, the development of such materials still faces a big challenge because of the limitation of intrinsic mechanism. Here, we reported that in-plane atomic-thick ferroelectricity can be induced by vertical electric field in phosphorene nanoribbons (PNRs). Through symmetry arguments, we predicted that ferroelectric direction is perpendicular to the direction of external electric field and lies in the plane. Further confirmed by the comprehensive first-principles calculations, we showed that such ferroelectricity is induced by the electron-polarization, which is different from the structural distortion in traditional ferroelectrics and the recent experimental discovery of in-plane atomic-thick ferroelectrics (Science 2016, 353, 274). Moreover, we found that the value of electronic polarization in bilayer is much larger than that in monolayer. Our results show that electron-polarization ferroelectricity maybe the most promising candidate for atomic-thick ferroelectrics.
authors.affiliation: Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education) and ‡Institute of Optoelectronics & Nanomaterials, Jiangsu Key Laboratory of Advanced Micro & Nano Materials and Technology, College of Material Science and Engineering, Nanjing University of Science and Technology , Nanjing, Jiangsu210094, P. R. China.
authors.forename: Ting
authors.initials: T
authors.lastname: Hu
authors.affiliation: Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education) and ‡Institute of Optoelectronics & Nanomaterials, Jiangsu Key Laboratory of Advanced Micro & Nano Materials and Technology, College of Material Science and Engineering, Nanjing University of Science and Technology , Nanjing, Jiangsu210094, P. R. China.
authors.forename: Haiping
authors.initials: H
authors.lastname: Wu
authors.affiliation: Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education) and ‡Institute of Optoelectronics & Nanomaterials, Jiangsu Key Laboratory of Advanced Micro & Nano Materials and Technology, College of Material Science and Engineering, Nanjing University of Science and Technology , Nanjing, Jiangsu210094, P. R. China.
authors.forename: Haibo
authors.initials: H
authors.lastname: Zeng
authors.affiliation: Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education) and ‡Institute of Optoelectronics & Nanomaterials, Jiangsu Key Laboratory of Advanced Micro & Nano Materials and Technology, College of Material Science and Engineering, Nanjing University of Science and Technology , Nanjing, Jiangsu210094, P. R. China.
authors.forename: Kaiming
authors.initials: K
authors.lastname: Deng
authors.affiliation: Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education) and ‡Institute of Optoelectronics & Nanomaterials, Jiangsu Key Laboratory of Advanced Micro & Nano Materials and Technology, College of Material Science and Engineering, Nanjing University of Science and Technology , Nanjing, Jiangsu210094, P. R. China.
authors.forename: Erjun
authors.initials: E
authors.lastname: Kan
keywords: Atomic-thick ferroelectrics; first-principles calculations; phosphorene; two-dimensional materials