Emergence of a new non-relativistic magnetic class: the discovery of altermagnets
Dr. Jairo Sinova
Johannes Gutenberg University Mainz, Germany
Location: 1080 Physics Research Building, Smith Seminar Room
Faculty Host: Chris Hammel
Abstract: Antiferromagnetic spintronics has been a very active research area of condensed matter in recent years. As we have learned how to manipulate antiferromagnets actively and their emergent topology, further surprises awaited. Turning off spin-orbit coupling, a new fresh view at the family of antiferromagnetic ordered systems reveals also an emergent new class, with properties characteristic of ferromagnets and antiferromagnets, as well as properties unique to itself. This third phase is characterized by compensated magnetic order and a spin-splitting momentum locking, suggesting its name altermagnetism. We show that this new phase is as abundant in nature as conventional ferromagnetism and antiferromagnetism. Its discovery as a distinct phase comes by using a non-relativistic spin-symmetry formalism which, counter to magnetic symmetries, delimits the phase uniquely. Material candidates ocurr in both three-dimensional and two-dimensional crystals, in diverse structural or chemistry types, and in conduction types covering the whole spectrum from insulators to superconductors. Altermagnets can have impact on prominent research areas, including spintronics, ultra-fast optics, neuromorphics, thermoelectrics, field-effect electronics, multiferroics, magnonics, valleytronics, magnetic topological matter, and unconventional superconductivity.
References:
[1] Libor Šmejkal, Jairo Sinova and Tomas Jungwirth, Altermagnetism: spin-momentum locked phase protected by non-relativistic symmetries, arXiv:2105.05820, PRX 2022
[2] Libor Šmejkal, Jairo Sinova and Tomas Jungwirth, Emerging research landscape of altermagnetism, arXiv:2204.10844; PRX 2022
[3] Zexin Feng, et al Observation of the Anomalous Hall Effect in a Collinear Antiferromagnet
arXiv:2002.08712; Nature Electronics 2022
[4] Libor Smejkal, et al, Anomalous Hall antiferromagnets, Nature Revies Materials 7, 482 (2022)
[5] Libor Šmejkal, et al, Giant and Tunneling Magnetoresistance in Unconventional Collinear Antiferromagnets with Nonrelativistic Spin-Momentum Coupling, Phys. Rev. X 12, 011028 (2022)
[6] Rafael González-Hernández, et al, Efficient Electrical Spin Splitter Based on Nonrelativistic Collinear Antiferromagnetism, Phys. Rev. Lett. 126, 127701 (2021)
[7] Libor Šmejkal, Rafael González-Hernández, T. Jungwirth and J. Sinova, Crystal time-reversal symmetry breaking and spontaneous Hall effect in collinear antiferromagnet, Sci. Adv. 6, 23 (2020)
The colloquium can also be seen on Zoom: https://osu.zoom.us/j/91292283159?pwd=Ryt1TUV2Z0NiZUIwWklRTE92WjZ1dz09
