Condensed Matter Journal Club: "Mapping Altermagnetic Symmetry through Quantum Oscillations in CrSb"

Altermagnets exhibit momentum-dependent spin splitting despite having compensated magnetic order. Establishing the symmetry of this splitting experimentally is essential for understanding their electronic properties. In this journal club, I will discuss recent quantum-oscillation measurements of CrSb that resolve its three-dimensional, g-wave altermagnetic spin texture. By tracking oscillation frequencies as the magnetic field rotates, the study identifies frequency branches that separate away from symmetry-enforced nodal orientations and merge upon approaching them. Comparison with electronic-structure calculations connects this angular evolution to the underlying magnetic symmetry. I will examine the evidence for assigning these branches to spin-split Fermi surfaces, discuss the interpretation’s limitations, and consider how quantum oscillations can probe unconventional magnetic order beyond conventional Fermi-surface characterization.