Valley piezoelectricity promoted by spin-orbit coupling in quantum materials  

作　　者：Yilimiranmu Rouzhahong Chao Liang Chong Li Biao Wang Huashan Li 

机构地区：[1]School of Physics,Sun Yat-sen University,Guangzhou 510275,China [2]Guangdong Provincial Key Laboratoryof Magetoelectric Physics and Devices,Schoolof Physics,Sun Yat-sen Universiy Guangzhou 510275,China [3]Center for Neutron Science and Technology,Schoolof Physics,Sun Yatsen University,Guangzhou 50275,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2023年第4期133-141,共9页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.52072417,and 11832019);NSFC Original Exploration Project(Grant No.12150001);Natural Science Foundation of Guangdong Province(Grant No.2018B030306036);Guangdong Science&Technology Project(Grant No.2019QN01C113);Project of Nuclear Power Technology Innovation Center of Science Technology and Industry for National Defense(Grant No.HDLCXZX-2021-HD-035);Guangdong International Science and Technology Cooperation Program(Grant No.2020A0505020005)。

摘　　要：Quantum materials have exhibited attractive electro-mechanical responses,but their piezoelectric coefficients are far from satisfactory due to the lack of feasible strategies to benefit from the quantum effects.We discovered the valley piezoelectric mechanism that is absent in the traditional piezoelectric theories yet promising to overcome this challenge.A theoretical model was developed to elucidate the valley piezoelectricity in 2D materials as originating from the strong spin-orbit coupling.Consistent analytical and density-functional-theory calculations validate the model and unveil the crucial dependence of valley piezoelectricity on valley/spin splitting and hybridization energy.Up to 50%of electro-mechanical responses in our tested twodimensional systems are attributed to the valley piezoelectric mechanisms.Rational strategies including doping,passivation,and external strain are proposed to optimize piezoelectricity,with a more than 127%increase in piezoelectricity demonstrated by density-functional-theory simulations.The general valley piezoelectric model not only opens an opportunity to achieve outstanding piezoelectricity via optimizing intrinsic variables but also makes the large family of valley materials promising for piezoelectric sensing and energy harvesting.

关 键 词：PIEZOELECTRICITY VALLEY modern polarization theory Berry curvature 

分 类 号：O413[理学—理论物理]