자료유형  

 학위논문

Control Number  

0017161738

International Standard Book Number  

9798384447566

Dewey Decimal Classification Number  

540

Main Entry-Personal Name  

Van Winkle, Madeline.

Publication, Distribution, etc. (Imprint  

[S.l.] : University of California, Berkeley., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

197 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-04, Section: B.

General Note  

Advisor: Bediako, D. Kwabena.

Dissertation Note  

Thesis (Ph.D.)--University of California, Berkeley, 2024.

Summary, Etc.  

요약Moire superlattices, formed by vertically stacking atomically thin van der Waals layers with a slight interlayer rotation and/or lattice constant difference, are a powerful platform for modulating the physicochemical behavior of two-dimensional solids. While the optical, electronic, and magnetic properties of moire materials can be intentionally tuned by changing the extent of crystallographic mismatch between constituent layers, structural perturbations such as lattice reconstruction, strain, and disorder also have a substantial impact on observed behavior. Therefore, directly measuring intrinsic structural deformations in moire superlattices, learning how to dynamically deform moire structures, and efforts toward correlative structure-property measurements are critical to understanding and controlling the emergent properties of these unique materials.In this dissertation, Chapter 1 first provides an introductory overview of recent developments in the field of two-dimensional materials and how the properties of these materials can be modified, including through construction of moire superlattices. This discussion is followed by a comprehensive look at the fundamentals of moire engineering, the role that structural deformations play in affecting moire properties, and the appeal of a diffraction-based imaging approach for linking the structure of moire architectures to observed properties and current theoretical models. Chapter 2 then describes the development of Bragg interferometry, a 4D-STEM-based imaging methodology for mapping moire structures, and the insights afforded by the methodology regarding the spontaneous lattice deformations driving reconstruction in twisted bilayer graphene, the effects of these deformations on flat band formation, and the impact of extrinsic heterostrain on reconstruction-induced strain fields. Chapter 3 explores the extension of Bragg interferometry to transition metal dichalcogenide (TMD) systems, providing evidence of distinct reconstruction mechanisms in twisted bilayer TMDs and heterobilayer TMDs. The compatibility of Bragg interferometry with different heterostructure geometries is also exploited to illuminate the effects of encapsulation layers on in-plane and out-of-plane reconstruction. Chapter 4 demonstrates the application of Bragg interferometry to functional devices for the first time, specifically for mapping the spatial arrangement of polar stacking domains in twisted trilayer WSe2. This information is then complemented by operando dark-field TEM imaging that uncovers a variety of electric field-driven structural responses in different twisted trilayer polytypes. Lastly, Chapter 5 provides a summary of the reported work and an outlook for future endeavours.

Subject Added Entry-Topical Term  

Chemistry.

Subject Added Entry-Topical Term  

Condensed matter physics.

Subject Added Entry-Topical Term  

Materials science.

Index Term-Uncontrolled  

Transition metal dichalcogenide systems

Index Term-Uncontrolled  

Physicochemical behavior

Index Term-Uncontrolled  

Moire structures

Index Term-Uncontrolled  

Mapping structural deformations

Added Entry-Corporate Name  

University of California, Berkeley Chemistry

Host Item Entry  

Dissertations Abstracts International. 86-04B.

Electronic Location and Access  

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Control Number  

joongbu:656887