{"title":"萤石型铁电候选材料中 HfO2 的独特开关模式†。","authors":"Ge-Qi Mao, Heng Yu, Kan-Hao Xue, Jinhai Huang, Zijian Zhou and Xiangshui Miao","doi":"10.1039/D4TC02418D","DOIUrl":null,"url":null,"abstract":"<p >As a technically significant dielectric, the physical understanding of ferroelectric hafnia is still not satisfactory. This is partly due to the limited number of sample materials in the fluorite-type ferroelectrics. In this work, five more fluorite-type ferroelectric candidate materials are further considered (SrI<small><sub>2</sub></small>, SrBr<small><sub>2</sub></small>, CaCl<small><sub>2</sub></small>, YbCl<small><sub>2</sub></small>, and YbBr<small><sub>2</sub></small>), in which their common features and the uniqueness of hafnia within this class are extracted. It was revealed that while other materials typically prefer to establish a new bond only after breaking an old bond during polarization switching, hafnia shows a strong tendency of forming a new bond first. The most favorable switching path of hafnia is thus very special and is not preferred by other materials. The reason for this is discussed within the context of the seven-coordination theory, and the indispensable covalent feature of the Hf–O bonds is identified as a key element. While the simultaneous ionic feature of Hf–O bonds permits HfO<small><sub>2</sub></small> to be a member of the fluorite-type ferroelectric class of materials, its covalent feature helps to restrict the switching path preference in HfO<small><sub>2</sub></small>, explaining its unique characteristics in this class. In addition, the special feature of fluorite-type ferroelectrics, compared with perovskite and wurtzite ferroelectrics, is also discussed and revealed from a structural point of view.</p>","PeriodicalId":84,"journal":{"name":"Journal of Materials Chemistry C","volume":null,"pages":null},"PeriodicalIF":5.7000,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Unique switching mode of HfO2 among fluorite-type ferroelectric candidates†\",\"authors\":\"Ge-Qi Mao, Heng Yu, Kan-Hao Xue, Jinhai Huang, Zijian Zhou and Xiangshui Miao\",\"doi\":\"10.1039/D4TC02418D\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >As a technically significant dielectric, the physical understanding of ferroelectric hafnia is still not satisfactory. This is partly due to the limited number of sample materials in the fluorite-type ferroelectrics. In this work, five more fluorite-type ferroelectric candidate materials are further considered (SrI<small><sub>2</sub></small>, SrBr<small><sub>2</sub></small>, CaCl<small><sub>2</sub></small>, YbCl<small><sub>2</sub></small>, and YbBr<small><sub>2</sub></small>), in which their common features and the uniqueness of hafnia within this class are extracted. It was revealed that while other materials typically prefer to establish a new bond only after breaking an old bond during polarization switching, hafnia shows a strong tendency of forming a new bond first. The most favorable switching path of hafnia is thus very special and is not preferred by other materials. The reason for this is discussed within the context of the seven-coordination theory, and the indispensable covalent feature of the Hf–O bonds is identified as a key element. While the simultaneous ionic feature of Hf–O bonds permits HfO<small><sub>2</sub></small> to be a member of the fluorite-type ferroelectric class of materials, its covalent feature helps to restrict the switching path preference in HfO<small><sub>2</sub></small>, explaining its unique characteristics in this class. In addition, the special feature of fluorite-type ferroelectrics, compared with perovskite and wurtzite ferroelectrics, is also discussed and revealed from a structural point of view.</p>\",\"PeriodicalId\":84,\"journal\":{\"name\":\"Journal of Materials Chemistry C\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.7000,\"publicationDate\":\"2024-07-31\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Materials Chemistry C\",\"FirstCategoryId\":\"1\",\"ListUrlMain\":\"https://pubs.rsc.org/en/content/articlelanding/2024/tc/d4tc02418d\",\"RegionNum\":2,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATERIALS SCIENCE, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Materials Chemistry C","FirstCategoryId":"1","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2024/tc/d4tc02418d","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
Unique switching mode of HfO2 among fluorite-type ferroelectric candidates†
As a technically significant dielectric, the physical understanding of ferroelectric hafnia is still not satisfactory. This is partly due to the limited number of sample materials in the fluorite-type ferroelectrics. In this work, five more fluorite-type ferroelectric candidate materials are further considered (SrI2, SrBr2, CaCl2, YbCl2, and YbBr2), in which their common features and the uniqueness of hafnia within this class are extracted. It was revealed that while other materials typically prefer to establish a new bond only after breaking an old bond during polarization switching, hafnia shows a strong tendency of forming a new bond first. The most favorable switching path of hafnia is thus very special and is not preferred by other materials. The reason for this is discussed within the context of the seven-coordination theory, and the indispensable covalent feature of the Hf–O bonds is identified as a key element. While the simultaneous ionic feature of Hf–O bonds permits HfO2 to be a member of the fluorite-type ferroelectric class of materials, its covalent feature helps to restrict the switching path preference in HfO2, explaining its unique characteristics in this class. In addition, the special feature of fluorite-type ferroelectrics, compared with perovskite and wurtzite ferroelectrics, is also discussed and revealed from a structural point of view.
期刊介绍:
The Journal of Materials Chemistry is divided into three distinct sections, A, B, and C, each catering to specific applications of the materials under study:
Journal of Materials Chemistry A focuses primarily on materials intended for applications in energy and sustainability.
Journal of Materials Chemistry B specializes in materials designed for applications in biology and medicine.
Journal of Materials Chemistry C is dedicated to materials suitable for applications in optical, magnetic, and electronic devices.
Example topic areas within the scope of Journal of Materials Chemistry C are listed below. This list is neither exhaustive nor exclusive.
Bioelectronics
Conductors
Detectors
Dielectrics
Displays
Ferroelectrics
Lasers
LEDs
Lighting
Liquid crystals
Memory
Metamaterials
Multiferroics
Photonics
Photovoltaics
Semiconductors
Sensors
Single molecule conductors
Spintronics
Superconductors
Thermoelectrics
Topological insulators
Transistors