Condensed Matter Seminar: Rafael Fernandes, University of Illinois
Topological properties of altermagnets
Event Details:
- Date: Monday, April 27, 2026
- Time: 10:00 - 11:00 AM
- Location: 1080 Physics Research Building
Abstract
Magnetism is the posterchild of how the interplay between electron-electron interactions and quantum physics promotes novel macroscopic phenomena, many of which hold a remarkable potential for technological applications. Recently, a new framework proposed to classify magnetic phases brought renewed interest in unconventional magnetic states, which are qualitatively distinct from ferromagnets and standard Néel antiferromagnets. Among those, altermagnetic phases have been met with enthusiasm by the scientific community, as they display properties found in both ferromagnets (like the splitting of electronic bands with opposite spins) and conventional antiferromagnets (like the absence of a net magnetization). Formally, what distinguishes these three different magnetic states are the crystalline symmetries that, when combined with time reversal, leave the system invariant. In the case of altermagnets, these symmetries endow the system with unique properties such as nodal spin-splitting and piezomagnetism. In this talk, I will show that, due to the interplay between these symmetries and spin-orbit coupling, altermagnets can host a wide range of non-trivial topological phenomena, such as protected nodal lines, mirror Chern bands, and spin-polarized Weyl nodal lines. I will argue that the topological properties of altermagnets arise from its intrinsic Berry curvature multipole, and discuss ways of detecting it experimentally via the elasto-Hall conductivity and the Hall viscosity.
Bio
Dr. Rafael Fernandes is a Professor of Physics at the University of Illinois Urbana-Champaign, where he has been since 2024. Before that, he was a Distinguished McKnight University Professor at the School of Physics and Astronomy of the University of Minnesota, where he was a faculty member from 2012 to 2024. Since 2025, he has also been the Lead Editor of the journal Physical Review Letters. Dr. Fernandes received his PhD at the University of Campinas, Brazil, in 2008 and held postdoctoral appointments at the Ames National Laboratory/Iowa State University and Columbia University/Los Alamos National Lab. He is a condensed matter theorist whose primary interest is on the microscopic understanding and modeling of the collective behavior of electrons in quantum materials, aiming at establishing a clear relationship between their microscopic behavior and their macroscopic properties.