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 |
|---|---|
| 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 |
|---|---|
| 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 |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Clara Michelle Nyby. |
|---|---|
| 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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