Dr. Libor Šmejkal

Phases of matter are classified according to order parameters and corresponding symmetries. For instance, water exhibits rotational symmetry, while ice breaks it. We have recently classified magnets by spin symmetries. We have found out that, remarkably, there exists yet third magnetic ordering in addition to the more common antiferromagnetic and ferromagnetic orderings. The unconventional altermagnetic ordering is characterised by an unconventional time-reversal symmetry breaking in the form of alternating spin order in reciprocal space which originates from anisotropic and mutually rotated opposite spin densities in direct space. Altermagnets are predicted a plethora of effects both of fundamental and applied interest such as dissipationless and spin-polarised currents, some of which were already indicated in experiments.

Our team is currently investigating altermagnetism and topological antiferromagnetic spintronics with our collaborators from Prague, Mainz, Washington, Barranquilla, Kaiserslautern, Frankfurt, Karlsruhe, Dresden, Grenoble, Nottingham, Vienna, and Pilsen.

 
Altermagnetism: Our prediction and perspective of altermagnetism are now published in Physical Review X! Here we show visualisation of altermagnetic spin densities. (C) LS & Matthias Greber

Altermagnetism: Our prediction and perspective of altermagnetism are now published in Physical Review X! Here we show visualisation of altermagnetic spin densities. (C) LS & Matthias Greber

Topological Antiferromagnetic Spintronics: Antiferromagnets with space-time symmetries exhibit Dirac fermions in their bandstructure.

Topological Antiferromagnetic Spintronics: Antiferromagnets with space-time symmetries exhibit Dirac fermions in their bandstructure.

 
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Current interests of our team:

  • Altermagnetism Perspective .
  • Topological Antiferromagnetic Spintronics Review .
  • Anomalous Hall effects Review .
  • Magnetoresistance effects Prediction of unconventional giant magnetoresistance .
  • Unconventional magnetism Prediction .
  • Axion matter Dark Matter Detection .

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    Recent Publications

      • “Beyond Conventional Ferromagnetism and Antiferromagnetism: A Phase with Nonrelativistic Spin and Crystal Rotation Symmetry”. L. Šmejkal, J.Sinova, and T. Jungwirth

    Physical Review X

      • “An anomalous Hall effect in altermagnetic ruthenium dioxide”. Zexin Feng*, Xiaorong Zhou*, Libor Šmejkal*, Lei Wu, Zengwei Zhu, Huixin Guo, Rafael González-Hernández, Xiaoning Wang, Han Yan, Peixin Qin, Xin Zhang, Haojiang Wu, Hongyu Chen, Ziang Meng, Li Liu, Zhengcai Xia, Jairo Sinova, Tomáš Jungwirth, and Zhiqi Liu

    Nature Electronics

      • “Crystal time-reversal symmetry breaking and spontaneous Hall effect in collinear antiferromagnets.”. L. Šmejkal, González-Hernández, R., T. Jungwirth, and J. Sinova

    Science Advances

      • “Topological antiferromagnetic spintronics”. Šmejkal, L., Mokrousov, Y., Yan, B. & MacDonald, A. H.

    Nature Physics

      • "Proposal to Detect Dark Matter using Axionic Topological Antiferromagnets". David J. E. Marsh, Kin Chung Fong, Erik W. Lentz, Libor Šmejkal, and Mazhar N. Ali

    Physical Review Letters

    Further interests - solid state theory of relativistic effects:

    • Prediction and observation of large anisotropic magnetoresistance in Mn2Au alloys. Press release .
    • Prediction and observation of anisotropic magnetoresistance and spin-orbit torque (SOT) in Heusler alloys. SOT was demonstrated at room temperature in NiMnSb microbars: Press release .

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