The scale-free ferroelectric polarization of fluorite MO_(2)(M=Hf,Zr)due to flat polar phonon bands are promising for nonvolatile memories.Defects are also widely introduced to improve the emergent ferroelectricity.Ho...The scale-free ferroelectric polarization of fluorite MO_(2)(M=Hf,Zr)due to flat polar phonon bands are promising for nonvolatile memories.Defects are also widely introduced to improve the emergent ferroelectricity.However,their roles are still not fully understood at the atomic-level.Here,we report a significant effect of point-defect-driven flattening of polar phonon bands with more polar modes and polarization contribution in doped MO_(2).The polar phonon bands in La-doped MO_(2)(M=Hf,Zr)can be significantly flattened,compared with pure ones.However,the lower energy barrier with larger polarization of VO-only doped MO_(2) compared with La-doped cases suggest that VO and local lattice distortion should be balanced for high-performance fluorite ferroelectricity.The work is believed to bridge the relation between point defects and the generally enhanced induced ferroelectricity in fluorite ferroelectrics at the atomic-level and inspire their further property optimization via defect-engineering.展开更多
基金W.D.acknowledges the National Key Research and Development Plan(2021YFA1202100)the Nature Science Foundation of Hubei province(20223564/2022CFB595)and China(52202134)+3 种基金2021 Independent Innovation Fund-New Teacher Research Starting Fund of Huazhong University of Science and Technology(5003182109)the Innovation Fund of WNLO,2022 Shenzhen Central Leading Local Science and Technology Development Special Funding Program Virtual University Park Laboratory ProjectQ.F.acknowledges the Natural Science Founda-tion of China(61971459)Shenzhen Technology Plan(JCYJ20190809095009521).
文摘The scale-free ferroelectric polarization of fluorite MO_(2)(M=Hf,Zr)due to flat polar phonon bands are promising for nonvolatile memories.Defects are also widely introduced to improve the emergent ferroelectricity.However,their roles are still not fully understood at the atomic-level.Here,we report a significant effect of point-defect-driven flattening of polar phonon bands with more polar modes and polarization contribution in doped MO_(2).The polar phonon bands in La-doped MO_(2)(M=Hf,Zr)can be significantly flattened,compared with pure ones.However,the lower energy barrier with larger polarization of VO-only doped MO_(2) compared with La-doped cases suggest that VO and local lattice distortion should be balanced for high-performance fluorite ferroelectricity.The work is believed to bridge the relation between point defects and the generally enhanced induced ferroelectricity in fluorite ferroelectrics at the atomic-level and inspire their further property optimization via defect-engineering.
