■ 제 목: Building 3D-oriented Nanoarchitectures to Harness Topological Defects and Nanomechanics
■ 연 사: 오명환 박사 (Lawrence Berkeley National Laboratory)
■ 일 시: 2020년 11월 2일(월) 오후 2시
■ 참가자 접속정보 (1:50분까지 참가를 부탁드립니다)
회의 ID: 808 075 7553
회의 비밀번호: 2020mse
회의 링크: https://kaist.zoom.us/j/8080757553
■ Abstract : Topological defects (i.e. dislocation, domain wall) play an essential role in the properties of crystalline materials and molecular assemblies. When the size of the crystallite or functional domain of the materials decreases to the nanometer scale, the defects predominantly determine those properties, opening up a variety of new applications. To date, however, neither bottom-up nor top-down methods for synthesizing nanocrystalline materials have been able to find a reliable way of controlling these defects, especially by manipulating the threedimensional (3D) rotational configuration of the domains. Looking at the most sophisticated molecular machinery, proteins, they have 3D-oriented structures whose remarkable functions emerge from 3D-dynamic interactions under the ordered potential landscapes from cell membranes. Herein, we demonstrate the delicate control of 3D heteroepitaxy using a lipid membrane-like synthetic system to grow various nano-crystallites, 3D organized with uniform grain-boundaries and related defects. In the resulting structures, the 3D-patterned strain field, which exists in the form of disclinations and dislocations, can be determined and even tailored with atomic precision. Furthermore, we have verified that the uniformity and discreteness of the defects enable us to obtain a direct correlation between the local strains/defects and collective electrochemical properties by performing nano-tomacro crystallography and spectroscopy. These middle-entropy nanomaterials, which allow fine-graining approaches, give us an invaluable opportunity to conduct nanomechanics of 3D organizations of interconnected and symmetry-related functional domains, study dynamics of electron, phonon, molecules, and defects within 3D-patterned potential energy landscapes, and explore novel quantum states from 3D coherent lattice and topological defects. Lastly, the current research focus to build next-generation functional nanomaterials for energy nanotechnology and nanoelectronics using this platform for 3D nanomechanics will be discussed.