Add to Calendar 2026-01-29T10:00:00 2026-01-29T11:00:00 Chiral Spin-Split Magnons in the Metallic Altermagnet CrSb Event Information: I will begin with a pedagogical overview of the recently identified magnetic class known as altermagnets, placing them in context alongside conventional ferromagnets and antiferromagnets. I will then present my research on investigating chiral magnons in the metallic altermagnet CrSb. This will include a discussion of the experimental challenges associated with probing magnons in metallic systems and the strategies used to overcome them. Finally, I will share results from polarized neutron diffraction and inelastic neutron scattering experiments on CrSb and introduce a new approach for determining chiral magnon splitting.   Ref:   [[2511.16086] Chiral Spin-Split Magnons in the Metallic Altermagnet CrSb           Emerging Research Landscape of Altermagnetism, Libor Šmejkal, Jairo Sinova and Tomas Jungwirth, Phys. Rev. X 12, 040501 Event Location: BRIM 311

Add to Calendar 2026-02-05T10:00:00 2026-02-05T11:00:00 Topological Landau theory Event Information: I will discuss a notion of topology “hidden” in Landau’s theory of phase transitions. When the order parameter comprises several components in the same irreducible representation of symmetry, it can possess a nontrivial topology and acquire a Berry phase under the variation of thermodynamic parameters. To illustrate this idea, I will focus on the superconducting phase transition of an electronic system with tetragonal symmetry and a two-component order parameter. From the time-dependent Ginzburg-Landau equation in the adiabatic limit, we find that the order parameter acquires a Berry phase after a cyclic evolution of parameters. I will discuss two concrete models — one preserving time-reversal symmetry and one breaking it — and show that the nontrivial topology of the order parameter originates from thermodynamic analogs of gapless Dirac and Weyl points in the phase diagram. Finally, I will propose an experimental realization of a thermodynamic Dirac point in chiral superconductors under strain, and its detectable signature in the Josephson effect, the geometry of vortices, and the upper critical field. Event Location: BRIM 311