SPICE Workshop on Nanomagnetism in 3D, April 30th - May 2nd 2024
Sinéad Griffen
At the heart of physics is the concept of symmetry - much of our understanding of condensed matter is rooted here, ranging from band structures, phonons and quasiparticles to more exotic phenomena found in quantum materials like topological insulators and superconductors. Largely absent from theories of quantum materials have been the more common amorphous, disordered and non-stoichiometric materials that do not possess ideal crystal symmetries. Here I will discuss our recent efforts at developing theoretical and computational approaches to describe the physics of non-crystalline materials, especially amorphous materials, with ab initio accuracy that incorporate their structural and chemical complexity. I will focus on the description of topological phases in amorphous solids, both in real and reciprocal space, and compare our results to recent experimental observations. In particular, I will introduce the concept of ‘structural spillage’ as a topological diagnostic for non-crystalline systems, allowing for the prediction of reciprocal space topology in an arbitrary system with chemical and structural specificity. I will conclude by discussing our amorphous spin Hamiltonian approach for the description of emergent topological magnetic structures in amorphous solids, including skyrmions, which allows us to identify the microscopic origins of magnetic superstructures such as topological defects.