Home > 게시판 > 세미나
2021.07.19 11:54
양자물질초전도연구실에서 KAIST 물리학과의 양찬호 교수님을 초청하여 아래와 같이 세미나를 개최합니다.
학과 구성원 여러분의 많은 참여를 부탁 드립니다.
온-오프 혼합으로 진행되는 세미나입니다.
===========================================================================
○ Title: Strongly Correlative Ionics
○ Speaker: 양 찬 호 교수님 (KAIST 물리학과)
○ Date/time: 2021. 7. 21. (Wed.) 11:00AM
○ 온라인 참여방법: 아래의 WebEx 링크 접속
https://skku-ict.webex.com/meet/koko1977
○ Place: Natural Science 1, Room No. 31214
○ Abstract: Long-range correlated fluctuations in order parameters occur at phase transition points, revealing emergent functionalities such as the morphotropic-phase-boundary driven high-k dielectrics, large piezoelectricity, and quantum paraelectricity. Likewise, the correlation length of thermal and quantum fluctuations of atomic positions can be divergently large at the critical point, leading to rapid and coherent ionic conduction. However, the lack of a lattice system that exhibits competing defect orderings has hindered study of the feasibility of this general thermodynamic wisdom. Here, we demonstrate that the activation energy associated with oxygen transport is sharply lowered in Ca-substituted bismuth ferrite (Bi1-xCaxFeO3-) thin films. Our demonstration relies on the finding that a compositional phase boundary between two isostructural phases with oxygen vacancy channel orderings competitively along the <100> or <110> crystal axes emerges at a chemical doping ratio. From first-principle calculations, we clarify that the effective short-range attraction between two positively charged oxygen vacancies sharing lattice deformation is the driving force of the long-range order and collective diffusion in the system. Our findings open a new avenue into strongly correlative ionics.
