Magnetism is one of the largest, most fundamental, and technologically most relevant fields of condensed-matter physics. Traditionally, two elementary magnetic phases have been distinguished - ferromagnetism and antiferromagnetism. The spin polarization in the electronic band structure reflecting the magnetization in ferromagnetic crystals underpins the broad range of time-reversal symmetry-breaking responses in this extensively explored and exploited type of magnets. By comparison, antiferromagnets have vanishing net magnetization. Recently, there have been observations of materials in which strong time-reversal symmetry-breaking responses and spin-polarization phenomena, typical of ferromagnets, are accompanied by antiparallel magnetic crystal order with vanishing net magnetization, typical of antiferromagnets [1]. A classification and description based on spin-symmetry principles offers a resolution of this apparent contradiction by establishing a third distinct elementary magnetic phase, dubbed altermagnetism [2]. We will start the talk with an overview of the still emerging unique phenomenology of this unconventional d-wave (or higher even-parity wave) magnetic phase, and of the wide array of altermagnetic materials. We will then show how altermagnetism can facilitate a development of ultra-fast and low-dissipation spintronic information technologies, and can have impact on a range of
other modern areas of condensed matter physics and nanoelectronics.
References
[1] L. Šmejkal, A. H. MacDonald, J. Sinova, S. Nakatsuji, T. Jungwirth, Nature Reviews Mater. 7, 482 (2022).
[2] L. Šmejkal, J. Sinova & T. Jungwirth, Phys. Rev. X (Perspective) 12, 040501 (2022).
