Probing the nature of excitations in spin-orbit-coupled materials from first principles

• Applicant: Professorin Dr. Maria Roser Valenti
• Subject Area: Theoretical Condensed Matter Physics
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 411289067

Understanding the nature of exotic magnetic states such as spin liquids and their excitations is a challenging task. Two main sources of difficulty are (i) a lack of a full microscopic description of experiments on suggested materials' realizations, and (ii) the fact that such states are rare in nature. Regarding the latter, in recent years spin-orbit-coupled quantum magnets have emerged as possible hosts of these type of unconventional states in relation to the Kitaev model.This project aims at contributing to the first challenge above by exploring the nature of spin-orbit-coupled quantum magnets, their excitations and the corresponding experimental response, with special emphasis on thermal transport and spectroscopic measurements. This will be pursued by a combination of first principles methods and numerical many-body techniques (exact diagonalization of finite systems, various mean field approaches as well as semiclassical and perturbative methods). We will first derive via first principles density functional theory studies and projection methods the appropriate pseudo-spin Hamiltonians and consider them as starting point to explore, with suitable many-body tools, response functions to compare with experimental measurements.We will also contribute to the second challenge above by designing from first principles material platforms with tuned spin interactions to manifest possible exotic magnetic phases.

• DFG Programme: Research Grants