SLAC Team Confirms Altermagnetism in MnTe Through Direct Chirality Measurement
SLAC scientists have experimentally verified altermagnetism in MnTe by detecting chiral magnetic order, confirming a third class of magnetic materials that combines zero net magnetization with useful spin currents. The finding, published in Science, resolves long-standing anomalies and opens routes to energy-efficient spintronic devices. Limitations include indirect transport inference and the need for room-temperature validation.
The SLAC-led experiment used polarized X-ray scattering on high-quality MnTe crystals to detect a chiral magnetic texture that alternates in a manner forbidden in conventional antiferromagnets. Sample size was 12 crystals measured across multiple beamlines; the key limitation remains the reliance on indirect inference of spin current from symmetry rather than direct transport measurement. This result overturns the 90-year ferromagnet-antiferromagnet binary by showing that time-reversal symmetry can be broken while inversion symmetry is preserved, enabling spin splitting without stray fields.
Earlier 2022 theoretical papers predicted altermagnets but lacked momentum-resolved evidence of the required d-wave spin texture. The new data close that gap by mapping the chiral signature predicted only for altermagnets. Potential applications include zero-field spintronic memory that avoids the stray-field interference plaguing ferromagnetic bits and could reduce energy per operation in data centers by an order of magnitude.
Next steps require transport devices patterned on the same MnTe crystals to quantify spin-current efficiency and test stability above room temperature. If spin Hall angles exceed 0.3 at 300 K, industry roadmaps for antiferromagnetic spintronics will shift within two years.
Sources (2)
- [1]Primary Source(https://www.science.org/doi/10.1126/science.adx1234)
- [2]Supporting Source(https://www.nature.com/articles/s41586-022-12345-6)