Topological transition from nodal to nodeless Zeeman splitting in altermagnets
Abstract: In an altermagnet, the symmetry that relates configurations with flipped magnetic moments is a rotation. This makes it qualitatively different from a ferromagnet, where no such symmetry exists, or a collinear antiferromagnet, where this symmetry is a lattice translation. In this paper, we investigate the impact of the crystalline environment, enabled by the spin-orbit coupling, on the magnetic and electronic properties of an altermagnet. We find that, because each component of the magnetization acquires its own angular dependence, the Zeeman splitting of the bands has symmetry-protected nodal lines residing on mirror planes of the crystal. Upon crossing the Fermi surface, these nodal lines give rise to pinch points that behave as single or double type-II Weyl nodes. We show that an external magnetic field perpendicular to these mirror planes can only move the nodal lines, such that a critical field value is necessary to collapse the nodes and make the Weyl pinch points annihilate. This unveils the topological nature of the transition from a nodal to a nodeless Zeeman splitting of the bands. We also classify the altermagnetic states of common crystallographic point groups in the presence of spin-orbit coupling, revealing that a broad family of magnetic orthorhombic perovskites can realize altermagnetism.
- I. Turek, Altermagnetism and magnetic groups with pseudoscalar electron spin, Phys. Rev. B 106, 094432 (2022).
- T. Aoyama and K. Ohgushi, Piezomagnetic Properties in Altermagnetic MnTeMnTe\mathrm{MnTe}roman_MnTe, arXiv:2305.14786 (2023).
- T. A. Maier and S. Okamoto, Weak-Coupling Theory of Neutron Scattering as a Probe of Altermagnetism, arXiv:2307.03793 (2023).
- L.-D. Yuan and A. Zunger, Degeneracy removal of spin bands in antiferromagnets with non-interconvertible spin motif pair, arXiv:2211.07803 (2022).
- S. Bhowal and N. A. Spaldin, Magnetic octupoles as the order parameter for unconventional antiferromagnetism, arXiv:2212.03756 (2022).
- I. Pomeranchuk, On the stability of a Fermi liquid, Sov. Phys. JETP 8, 361 (1958).
- C. Ederer and N. A. Spaldin, Towards a microscopic theory of toroidal moments in bulk periodic crystals, Phys. Rev. B 76, 214404 (2007).
- S. Hayami and H. Kusunose, Microscopic description of electric and magnetic toroidal multipoles in hybrid orbitals, J. Phys. Soc. Jpn. 87, 033709 (2018).
- H. Kusunose, Description of multipole in f-electron systems, J. Phys. Soc. Jpn. 77, 064710 (2008).
- C.-K. Chiu and A. P. Schnyder, Classification of reflection-symmetry-protected topological semimetals and nodal superconductors, Phys. Rev. B 90, 205136 (2014).
- E. Bousquet and N. Spaldin, Induced Magnetoelectric Response in Pnma𝑃𝑛𝑚𝑎Pnmaitalic_P italic_n italic_m italic_a Perovskites, Phys. Rev. Lett. 107, 197603 (2011a).
- E. Bousquet and N. Spaldin, Induced Magnetoelectric Response in Pnma𝑃𝑛𝑚𝑎Pnmaitalic_P italic_n italic_m italic_a Perovskites, Phys. Rev. Lett. 107, 197603 (2011b).
- D. M. Hatch and H. T. Stokes, INVARIANTS: program for obtaining a list of invariant polynomials of the order-parameter components associated with irreducible representations of a space group, J. Appl. Crystallogr. 36, 951 (2003).
- A. Knoll and C. Timm, Classification of Weyl points and nodal lines based on magnetic point groups for spin-1212\frac{1}{2}divide start_ARG 1 end_ARG start_ARG 2 end_ARG quasiparticles, Phys. Rev. B 105, 115109 (2022).
- R. M. Fernandes and J. Schmalian, Scaling of nascent nodes in extended-s𝑠sitalic_s-wave superconductors, Phys. Rev. B 84, 012505 (2011).
- M. Khodas and A. V. Chubukov, Vertical loop nodes in iron-based superconductors, Phys. Rev. B 86, 144519 (2012).
- I. I. Mazin, Notes on altermagnetism and superconductivity, arXiv:2203.05000 (2022).
- M. Papaj, Andreev reflection at altermagnet/superconductor interface, arXiv:2305.03856 (2023).
- G. Kresse and J. Hafner, Ab initio molecular dynamics for liquid metals, Phys. Rev. B 47, 558 (1993).
- G. Kresse and J. Furthmüller, Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set, Comput. Mater. Sci. 6, 15 (1996).
- G. Kresse and J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set, Phys. Rev. B 54, 11169 (1996).
Paper Prompts
Sign up for free to create and run prompts on this paper using GPT-5.
Top Community Prompts
Collections
Sign up for free to add this paper to one or more collections.