DC Field | Value | Language |
---|---|---|
dc.contributor.advisor | Yang, Chan-Ho | - |
dc.contributor.advisor | 양찬호 | - |
dc.contributor.author | 윤신희 | - |
dc.date.accessioned | 2022-04-15T01:53:47Z | - |
dc.date.available | 2022-04-15T01:53:47Z | - |
dc.date.issued | 2020 | - |
dc.identifier.uri | http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=986300&flag=dissertation | en_US |
dc.identifier.uri | http://hdl.handle.net/10203/294560 | - |
dc.description.abstract | Ferroelastic twin wall is a contact surface of two bulk crystals with different orientations, at which intriguing properties emerge, such as polarity, conductivity, ion accumulation, and magnetization pinning effect absent in the bulk. Although twin walls with a nanoscale width occupy a small volume in a crystal, emergent properties at twin walls can dominate the whole properties of a crystal. Therefore, finding a new functionality emerging at twin walls is important not only for nanodevice applications but also to reveal emerging physical properties. In this thesis, flexopiezoelectricty is introduced as a new phenomenon at twin walls. Despite piezoelectric response has been expected to exist at twin walls, the phenomenon has not been directly observed and explained due to the lack of appropriate materials. We have successfully synthesized WO3 epitaxial films with a hierarchical ferroelastic twin structure. We analyze the strain gradient at twin walls and explore the existence of flexopiezoelectricity. Flexopiezoelectricity is a new phenomenon described by a trilinear free energy density of polarization, strain, and strain gradient. It is the origin of the piezoelectric response at a twin wall, where a large strain gradient exists, in a centrosymmetric material. Successful characterization of flexopiezoelectric symmetry and coefficient along with control of twin wall orientation provide a useful pathway into twin wall electromechanics. | - |
dc.language | eng | - |
dc.title | Flexopiezoelectricity at ferroelastic WO3 twin walls | - |
dc.title.alternative | 텅스텐산화물 강탄성 쌍도메인 벽에서의 변형구배로 인한 압전효과 연구 | - |
dc.identifier.CNRN | 325007 | - |
dc.description.department | 한국과학기술원 :물리학과, | - |
dc.description.isOpenAccess | 학위논문(박사) - 한국과학기술원 : 물리학과, 2020.2,[iv, 91 p. :] | - |
dc.publisher.country | 한국과학기술원 | - |
dc.type.journalArticle | Thesis(Ph.D) | - |
dc.subject.keywordAuthor | Twin wall▼aStrain gradient▼aFlexopiezoelectricity▼aTungsten trioxide▼aPiezoresponse force microscopy | - |
dc.subject.keywordAuthor | 쌍도메인 벽▼a변형구배▼a변형구배압전성▼a텅스텐산화물▼a압전감응현미경 | - |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.