Comment on "Andreev Reflection to Probe Momentum-Dependent Spin Polarization in Altermagnet CrSb"
Year: 2026
Type: preprint
Abstract: Zhang et al. [Phys. Rev. Lett. 137, 016701 (2026)] report momentum-dependent spin polarization in the altermagnet CrSb from point-contact Andreev reflection along the (0001), (-1-120), and (10-10) directions. We show that the Andreev spin polarization they claim to measure is forbidden by symmetry: it vanishes identically in the diffusive regime for all directions in CrSb, and in the ballistic regime for two of the three orientations measured. It is allowed only along one direction, where the calculated band structure gives ~50%. The large, nearly isotropic values reported follow from an incorrect definition of ballistic Andreev spin polarization that evaluates the spin asymmetry at fixed three-dimensional momentum; the Andreev selection rule is local only in the momentum component parallel to the interface. Moreover, the ballistic regime is not demonstrated, and the fitting procedure is flawed.
Source: arXiv (Cornell University)
Authors: Mazin, Igor I., Khodas, Maxim, Nadgorny, Boris
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7214076343