Frustration and disorder: classical spin liquids and Floquet-Anderson insulators
<p>In this thesis, the physics of two systems is investigated, both of which support unconventional phases of matter. We investigate a frustrated system which has a classical spin liquid regime in the paramagnetic phase. We also consider a periodically-driven, disordered system and explore...
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Published: |
2017
|
| _version_ | 1826300720082583552 |
|---|---|
| author | Liu, D |
| author2 | Chalker, J |
| author_facet | Chalker, J Liu, D |
| author_sort | Liu, D |
| collection | OXFORD |
| description | <p>In this thesis, the physics of two systems is investigated, both of which support unconventional phases of matter. We investigate a frustrated system which has a classical spin liquid regime in the paramagnetic phase. We also consider a periodically-driven, disordered system and explore nonequilibrium regimes. Both systems exhibit macroscopic behaviour which differs strongly from the behaviour in standard scenarios.</p> <p>First, the properties of frustrated magnets and related systems are discussed. We introduce three-dimensional generalisations of a well-studied two-dimensional frustrated system. These generalisations consist of coupled layers of two-dimensional triangular lattice Ising antiferromagnets. We study three stackings that have nearest-neighbour interactions: two frustrated stackings (abc and abab) and the unfrustrated stacking (aaa). We use a combination of methods, including numerics and analytics, to show that these generalisations exhibit a strongly correlated, highly fluctuating regime known as a classical spin liquid. We show this by investigating the structure factor and correlations directly and by describing a mapping to a continuum field theory that gives further clarity about the classical spin liquid regime using a renormalisation group analysis and consideration of low-lying excitations in these systems.</p> <p>Second, we study the response of a disordered system to a time-periodic driving potential. We start in the context of Mott's work on a.c. conductivity in Anderson insulators and move beyond this to study the Floquet (long-time) regimes beyond linear response. Using Landau-Zener physics, we construct a description of the various regimes which are possible. We also present the results of thorough numerical studies of these systems.</p> |
| first_indexed | 2024-03-07T05:21:27Z |
| format | Thesis |
| id | oxford-uuid:df0f470c-67b1-4542-8c30-4ec42852be6b |
| institution | University of Oxford |
| last_indexed | 2024-03-07T05:21:27Z |
| publishDate | 2017 |
| record_format | dspace |
| spelling | oxford-uuid:df0f470c-67b1-4542-8c30-4ec42852be6b2022-03-27T09:36:37ZFrustration and disorder: classical spin liquids and Floquet-Anderson insulatorsThesishttp://purl.org/coar/resource_type/c_db06uuid:df0f470c-67b1-4542-8c30-4ec42852be6bORA Deposit2017Liu, DChalker, J<p>In this thesis, the physics of two systems is investigated, both of which support unconventional phases of matter. We investigate a frustrated system which has a classical spin liquid regime in the paramagnetic phase. We also consider a periodically-driven, disordered system and explore nonequilibrium regimes. Both systems exhibit macroscopic behaviour which differs strongly from the behaviour in standard scenarios.</p> <p>First, the properties of frustrated magnets and related systems are discussed. We introduce three-dimensional generalisations of a well-studied two-dimensional frustrated system. These generalisations consist of coupled layers of two-dimensional triangular lattice Ising antiferromagnets. We study three stackings that have nearest-neighbour interactions: two frustrated stackings (abc and abab) and the unfrustrated stacking (aaa). We use a combination of methods, including numerics and analytics, to show that these generalisations exhibit a strongly correlated, highly fluctuating regime known as a classical spin liquid. We show this by investigating the structure factor and correlations directly and by describing a mapping to a continuum field theory that gives further clarity about the classical spin liquid regime using a renormalisation group analysis and consideration of low-lying excitations in these systems.</p> <p>Second, we study the response of a disordered system to a time-periodic driving potential. We start in the context of Mott's work on a.c. conductivity in Anderson insulators and move beyond this to study the Floquet (long-time) regimes beyond linear response. Using Landau-Zener physics, we construct a description of the various regimes which are possible. We also present the results of thorough numerical studies of these systems.</p> |
| spellingShingle | Liu, D Frustration and disorder: classical spin liquids and Floquet-Anderson insulators |
| title | Frustration and disorder: classical spin liquids and Floquet-Anderson insulators |
| title_full | Frustration and disorder: classical spin liquids and Floquet-Anderson insulators |
| title_fullStr | Frustration and disorder: classical spin liquids and Floquet-Anderson insulators |
| title_full_unstemmed | Frustration and disorder: classical spin liquids and Floquet-Anderson insulators |
| title_short | Frustration and disorder: classical spin liquids and Floquet-Anderson insulators |
| title_sort | frustration and disorder classical spin liquids and floquet anderson insulators |
| work_keys_str_mv | AT liud frustrationanddisorderclassicalspinliquidsandfloquetandersoninsulators |