Ultrafast structural dynamics in layered transition metal dichalcogenides
Abstract/Contents
- Abstract
- This work focuses on visualizing and manipulating atomic-scale structural changes in transition metal dichalcogenide (TMD) materials, with the goals of understanding fundamental light-matter interactions in these materials and modulating material properties at an ultrafast time scale. Tungsten ditelluride is a layered TMD that crystallizes in a distorted hexagonal net with an orthorhombic unit cell (Td phase). The lack of inversion symmetry in this phase leads to a predicted new topological semimetal hosting the so-called type-II Weyl points. Here, we use a single THz pulse to trigger a structural phase transition to a centrosymmetric phase, and probe the switching using an ultrafast electron diffraction technique. These findings serve as the first direct evidence of a THz field induced structural transition in a two-dimensional material, and offer a new promising way to optically control the topological properties of solids. Additionally, we present a new non-destructive method for probing heat transport in nanoscale crystalline materials using time-resolved x-ray measurements of photo-induced strain. This technique directly probes time-dependent temperature changes in the crystal and the subsequent relaxation across buried interfaces by measuring changes in the c-axis lattice spacing after optical excitation. This work is motivated by the need to understand the fundamentals of nanoscale heat propagation, particularly at buried interfaces in functional devices.
Description
Type of resource | text |
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Form | electronic resource; remote; computer; online resource |
Extent | 1 online resource. |
Place | California |
Place | [Stanford, California] |
Publisher | [Stanford University] |
Copyright date | 2019; ©2019 |
Publication date | 2019; 2019 |
Issuance | monographic |
Language | English |
Creators/Contributors
Author | Nyby, Clara M | |
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Degree supervisor | Heinz, Tony F | |
Degree supervisor | Lindenberg, Aaron Michael | |
Thesis advisor | Heinz, Tony F | |
Thesis advisor | Lindenberg, Aaron Michael | |
Thesis advisor | Chidsey, Christopher E. D. (Christopher Elisha Dunn) | |
Degree committee member | Chidsey, Christopher E. D. (Christopher Elisha Dunn) | |
Associated with | Stanford University, Department of Chemistry. |
Subjects
Genre | Theses |
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Genre | Text |
Bibliographic information
Statement of responsibility | Clara Michelle Nyby. |
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Note | Submitted to the Department of Chemistry. |
Thesis | Thesis Ph.D. Stanford University 2019. |
Location | electronic resource |
Access conditions
- Copyright
- © 2019 by Clara M Nyby
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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