Direct observation of chiral spin signals in manganese telluride

Researchers led by the U.S. Department of Energy's SLAC National Accelerator Laboratory reported direct observation of a "handle" magnon—a signature of altermagnetism—in manganese telluride (MnTe), publishing the findings in Science on October 29. Using circularly polarized X-ray scattering, the team found that the momentum-dependent variation of spin polarization matches the altermagnetic g-wave symmetry of MnTe, which they say provides experimental evidence for altermagnetism. Altermagnets combine features of ferromagnets and antiferromagnets, with net magnetization canceling out while still supporting spin-polarized currents, making them a focus for spin-based electronics research. The result matters because altermagnetism has largely been a theoretical prediction, and a direct magnon measurement in a real material could accelerate work on spintronic devices. What to watch next is whether other candidate altermagnets show the same g-wave magnon signature and whether the effect can be exploited in practical spin-current components.