文献类型：期刊文献

英文题名：Strain Engineering for 2D Ferroelectricity in Lead Chalcogenides

作者：Xu, Tao[1];Wang, Xiaoyuan[2];Mai, Jiawei[1];Zhang, Jingtong[3];Wang, Jie[3];Zhang, Tong-Yi[1]

机构：[1]Shanghai Univ, Mat Genome Inst, Shanghai 200444, Peoples R China;[2]East China Univ Sci & Technol, Key Lab Pressure Syst & Safety, Minist Educ, Shanghai 200237, Peoples R China;[3]Zhejiang Univ, Sch Aeronaut & Astronaut, Dept Engn Mech, Hangzhou 310027, Zhejiang, Peoples R China

年份：2020

卷号：6

期号：1

外文期刊名：ADVANCED ELECTRONIC MATERIALS

收录：;EI(收录号：20194707718065);WOS:【SCI-EXPANDED(收录号:WOS:000496829700001)】；

基金：The authors acknowledge the financial support from the National Natural Science Foundation of China (Grant No. 11802169 and No. 11602252) and Fundamental Research Funds for the Central Universities (Grant No. 50321071915017).

语种：英文

外文关键词：2D materials; ferroelectric photovoltaic materials; ferroelectricity; strain engineering

摘要：The quest for new 2D ferroelectric materials continues to arouse interest. Based on first-principles calculations, here, 2D ferroelectric properties in lead chalcogenides PbXs (X = S, Se, and Te) with a thickness of two atomic layers via strain engineering is demonstrated. Although these materials are stable in a rocksalt-type cubic structure and are intrinsically nonferroelectric materials, an appropriate mechanical strain can readily activate a paraelectric to ferroelectric phase transition and induce in-plane electric polarization in these atomic layers. The induced polarization magnitude can be as large as 1.90 x 10(-10) C m(-1) at a biaxial strain of epsilon = 4.0%, which is comparable in magnitude to that of ultrathin ferroelectric SnTe. The Curie temperature T-c of the materials is also estimated using effective Hamiltonian simulations. The origin of the emerged ferroelectric phase is attributed to softening of the polar mode with applied strain. In addition, the band gaps of the crystals are found to be tunable with applied strain, which can be adjusted to the ideal value of 1.3 eV for photovoltaic applications. The results not only provide a new route to explore ferroelectricity in 2D materials but also suggest promising semiconducting ferroelectrics for solar applications.