New Magnetic Material Exhibiting Altermagnetism Discovered at Room Temperature

allanweton

For decades, physics research centered around two main forms of magnetism: ferromagnetism, where electron spins align in the same direction, and antiferromagnetism, where spins align in alternating opposite directions. However, recent discoveries have introduced a third, distinct type—altermagnetism.

Altermagnetism defies conventional classification. It breaks time-reversal symmetry, features spin-split electronic band structures, and yet retains a net zero magnetization. Now, researchers from the Chinese Academy of Sciences and collaborating institutions have identified a new material, KV₂Se₂O, that exhibits altermagnetic behavior at room temperature—a significant breakthrough published in Nature Physics.

“KV₂Se₂O is part of a larger family of compounds with the [T₂Q₂O]²⁻ layered structure, where T represents a 3d transition metal and Q can be S, Se, As, Sb, or Bi,” explained Tian Qian, senior author of the study. “These materials host a variety of complex phenomena, including superconductivity, Mott insulating states, and charge or spin density waves.”

The team initially aimed to study the origins of KV₂Se₂O’s unconventional superconductivity, previously linked to a spin-density-wave-like transition around 100 K. To investigate further, they synthesized high-quality single crystals and conducted a series of measurements—including resistivity, magnetic susceptibility, specific heat, ARPES (angle-resolved photoemission spectroscopy), NMR, and STM—alongside detailed electronic band structure calculations.

https://github.com/BrentGNT/Arch2

https://github.com/TomGMN/ffkoa

https://github.com/BryanEMD/kkstb

https://github.com/CodyEGT/Sfumm

https://github.com/ErikBDT/Fcumg

https://github.com/DorianKVT/Mwum

https://github.com/JeremyEGT/Ahum9

https://github.com/AidenBMT/Wmumd

https://github.com/BlakeTNS/S2ugm

https://github.com/BrettKNO/Zadzmg

https://github.com/BrodyTNN/Cscofps

https://github.com/CalebSNT/Bmumg

https://github.com/CarterSMN/KtbsK

https://github.com/ChaseDNT/Trucg

https://github.com/CooperTRN/Sf2ueg

https://github.com/DaltonYNT/Ssumg

https://github.com/EthanGNM/Wwhug

https://github.com/JacksonMRT/Bwum

https://github.com/AtevenKLD/Wtmum

https://github.com/JoshBDO/Coum5

“NMR results showed that vanadium atoms form a long-range magnetic order above room temperature, with antiparallel spin alignment along the c-axis,” said Qian. “This compensated collinear magnetic configuration is a key characteristic of altermagnetism.”

ARPES data confirmed that KV₂Se₂O is metallic and revealed a band structure consistent with theoretical predictions of an altermagnetic phase. Spin-resolved ARPES further showed momentum-dependent spin polarization with a d-wave symmetry—a hallmark feature of altermagnetism.

While superconductivity wasn’t observed, the researchers confirmed that KV₂Se₂O exhibits spin-split bands tied to altermagnetic ordering at temperatures above room temperature.

“The key discovery is a metallic altermagnet with d-wave spin splitting stable at room temperature,” said Qian. “Its C₂-symmetric, spin-polarized Fermi surface suggests the potential for generating highly polarized electrical currents and large spin currents—ideal for next-generation spintronic devices.”

This new material provides a valuable platform for further research into altermagnetism and its interaction with other quantum phenomena. In future studies, the team plans to explore how altermagnetism could interface with other exotic states of matter, including unconventional superconductivity.

“Interestingly, the V₂O planes in KV₂Se₂O have a structure that is the inverse of CuO₂ planes found in high-temperature superconductors,” Qian noted. “This structural compatibility could allow us to study interfacial physics between d-wave superconductors and altermagnets, opening up exciting new directions in quantum materials research.”