Disordered magnets: ground state, excitations, and thermodynamics
| Grant number: | 19/17645-0 |
| Support type: | Scholarships in Brazil - Doctorate |
| Effective date (Start): | November 01, 2019 |
| Effective date (End): | January 31, 2023 |
| Field of knowledge: | Physical Sciences and Mathematics - Physics - Condensed Matter Physics |
| Principal Investigator: | Eric de Castro e Andrade |
| Grantee: | Igor César de Almeida |
| Home Institution: | Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil |
Abstract Disorder is always present in solids. Typical examples of disorder in magnets described by local spin moments are the lack or presence of extra spins, caused, for example, by the intentional or unintentional chemical substitution of elements during the growth of the samples. In this project, we will study frustrated disordered spin-S antiferromagnets that, in their homogeneous limit, show magnetic long-ranged magnetic order in their ground state. We will then consider the effects of inhomogeneities, usually vacancies or modulations on the magnetic couplings, in this long-range order, especially where these defects suppress ordering. We seek to identify not only the resulting ground states, for example, a spin-glass or a random singlet phase, but also the spectrum of low energy excitations. Thus, we will study the characteristic signatures of these phases by analyzing their thermodynamic, spectroscopic, and transport responses. To implement this program, we will use a combination of techniques such as mean-field theory, perturbation theory, and spin-waves. (AU) | |