eprintid: 10188848
rev_number: 8
eprint_status: archive
userid: 699
dir: disk0/10/18/88/48
datestamp: 2024-04-26 11:59:04
lastmod: 2024-04-26 11:59:04
status_changed: 2024-04-26 11:59:04
type: thesis
metadata_visibility: show
sword_depositor: 699
creators_name: Smith, Rachael Louise
title: Stacking Disorder as a Critical Tuning Parameter for the
Properties of Materials
ispublished: unpub
divisions: UCL
divisions: B04
divisions: C06
divisions: F56
note: Copyright © The Author 2023. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/).  Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms.  Access may initially be restricted at the author’s request.
abstract: Stacking disorder is a complex yet vital phenomenon that in principle, can occur in every
layered material.1-9 The need for a thorough understanding of stacking disorder has only
become apparent within the last 12 years, 10 together with the extensive impact this has
on material properties. This thesis builds upon stacking disorder research explored
previously for diamond 2, 7, 11, 12 in addition to new studies on AgI, CuI, AgI-CuI, and
provides insight into the theoretical aspects of stacking disorder and third-order memory
effects.
This thesis focuses initially on stacking disorder in AgI, where it has been found
that the dependence of the Ag+ and I- ratios allows for targeted precipitation of cubicities
in the 0–81% range. AgI samples exhibiting varying polarity, originating from preparation
method, have been shown to experience surface ion adsorption effects with cations. A link
between AgI cubicity and associated band gap energies has also been found. In addition,
when heating AgI to the high temperature α-phase, samples exhibited memory effects,
and this is hypothesised to relate to the surface stabilisation by ions.
CuI did not exhibit any stacking disorder, however this research has given greater
insight into the characteristics of this material. Stacking disorder in AgI-CuI was explored
by adjusting the starting ratios of ions, showing a tendency of the resultant material to
form cubic polytypes amongst potential new phases and stacking disordered structures
when a deficiency of I- was exploited.
Investigations into Popigai diamond samples showed hexagonalities of 0-39%.
Additional peaks in XRD patterns at 2θ=12 ° in combination with DIFFaX simulations
and HRTEM suggested the presence of extended graphitic regions resulting in both type
1 and 2 diaphite.
The final chapter focuses on evolving theoretical aspects of stacking disorder,
developing MCDIFFaX to incorporate third-order stacking probabilities and fitting of
high-order memory effect simulations.
date: 2024-03-28
date_type: published
oa_status: green
full_text_type: other
thesis_class: doctoral_open
thesis_award: Ph.D
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 2256456
lyricists_name: Smith, Rachael
lyricists_id: RLSMI21
actors_name: Smith, Rachael
actors_name: Mustafa, Adelat
actors_id: RLSMI21
actors_id: AMUST21
actors_role: owner
actors_role: impersonator
full_text_status: public
pages: 314
institution: UCL (University College London)
department: Chemistry
thesis_type: Doctoral
citation:        Smith, Rachael Louise;      (2024)    Stacking Disorder as a Critical Tuning Parameter for the Properties of Materials.                   Doctoral thesis  (Ph.D), UCL (University College London).     Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10188848/1/Rachael_Smith_Rachael%20L%20Smith%20-%20PhD%20Thesis%20-%2013023837.pdf