3D quantum-oscillation mapping reveals g-wave altermagnetic order in CrSb

The team performed high-field torque magnetometry and proximity-detector oscillator measurements to obtain a three-dimensional quantum-oscillation map of CrSb’s electronic structure. Rotating the magnetic field through various crystallographic directions revealed that the exchange splitting between up- and down-spin bands follows the \({{\mathcal{Y}}}_{4}^{-3}=yz(3x^{2}-y^{2})\) spherical harmonic, indicating a g-wave altermagnetic order parameter.

In symmetry-protected nodal planes the spin-split Fermi sheets become degenerate, yielding a single oscillation frequency, while in antinodal orientations the frequencies split, providing a clear altermagnetic signature. Effective masses extracted from temperature-dependent data satisfy the predicted relation \(m_{\uparrow}^{*}/m_{\downarrow}^{*}=\sqrt{f_{\uparrow}/f_{\downarrow}}\), confirming the spin-split origin. Adjusted density-functional calculations reproduce the observed “dogbone” Fermi pocket geometry. With an ordering temperature near 740 K, residual resistivity around 2 μΩ·cm and robust crystal quality, CrSb stands out as a promising platform for low-energy spintronic devices.