Event announcement as pdf-Download (https://tu-dresden.de/mn/phys ik/ressourcen/dateien/physikalisches-kolloquium/2025-04-29-Phys_Kolloq-Sme jkal-SoSe2025.pdf).
Abstract: Symmetries play a k ey role in many areas of modern physics. For example\, the symmetry-breaki ng paradigm describes how various phases of matter emerge. In magnetism\, spontaneous symmetry breaking leads to well-known phases of ferromagnets a nd antiferromagnets. Ferromagnets have a net magnetization\, while antifer romagnets have atomic magnetic moments that cancel out. Surprisingly\, rec ent research shows this magnetic dichotomy\, developed in the 1930s\, is i ncomplete. In this talk\, we introduce a previously overlooked way to clas sify magnetic phases using spin- lattice symmetries. These are combined op erations in both spin and crystal space. This approach led us to discover two new quantum phases: altermagnets and antialtermagnets. Both have compe nsated magnetic order\, similar to antiferromagnets. Simultaneously\, they also show spin-polarization in their electronic structures similar to fer romagnets. The main difference between altermagnets and antialtermagnets i s their behaviour under time reversal. Altermagnetic electronic structure breaks it\, leading to features like d-wave spin order. In contrast\, the antialtermagnetic electronic structure preserves time-reversal symmetry an d shows\, for example\, the p-wave spin order. We’ll also discuss how th e discovery of altermagnets was motivated by our earlier work predicting a n unconventional spontaneous Hall effect. Furthermore\, we will overview p hotoemission experiments which recently confirmed altermagnetic order in M nTe and CrSb materials. Finally\, we will explore how altermagnetism and s pin symmetries can benefit other fields. These include spintronics\, magno nics\, topological and 2D materials\, and multiferroics. All offer promisi ng paths to faster\, smaller\, and more energy-efficient nanoelectronic de vices.
Short bio: Libor Šmejkal is a head of t he Functional Quantum Matter Group at the Max Planck Institute for the Phy sics of Complex Systems in Dresden. After studying theoretical and experim ental physics in Brno and Vienna\, he received his PhD in 2020 in Prague a nd later led a research team in Mainz. His research focuses on quantum mat ter\, including altermagnets and spintronic functionalities. His scientifi c contributions have been recognized with several awards\, including the W alter Schottky Prize (2025)\, an ERC Starting Grant (2024)\, the Falling W alls Science Breakthrough of the Year (2023)\, the European Magnetism Asso ciation Young Scientist Award (2021)\, the Czech Head Prize (2021)\, and t he Siemens Award (2020).
DTSTAMP:20260316T215535Z CREATED:20250428T053901Z LAST-MODIFIED:20250429T054012Z END:VEVENT END:VCALENDAR