Theory of orbital magnetic quadrupole moment and magnetoelectric susceptibility

ORAL

Abstract

We derive a quantum-mechanical formula of the orbital magnetic quadrupole moment (MQM) in periodic systems by using the gauge-covariant gradient expansion. This formula is valid for insulators and metals at zero and nonzero temperature. We also prove a direct relation between the MQM and magnetoelectric (ME) susceptibility for insulators at zero temperature. It indicates that the MQM is a microscopic origin of the ME effect. Using the formula, we quantitatively estimate these quantities for room-temperature antiferromagnetic semiconductors BaMn2As2 and CeMn2Ge2−xSix . We find that the orbital contribution to the ME susceptibility is comparable with or even dominant over the spin contribution.

[1] A. Shitade, H. Watanabe, and Y. Yanase, Phys. Rev. B 98, 020407(R) (2018).

*This work was supported by Grants-in-Aid for Scientific Research on Innovative Areas “JPhysics” (Grant No. JP15H05884) and “Topological Materials Science” (Grant No. JP16H00991) from the Japan Society for the Promotion of Science (JSPS), and by JSPS KAKENHI (Grants No. JP15K05164 and No. JP15H05745).

–

Presenters

  • Atsuo Shitade

    • RIKEN Center for Emergent Matter Science

Authors

  • Atsuo Shitade

    • RIKEN Center for Emergent Matter Science

  • Hikaru Watanabe

    • Department of Physics, Kyoto University

  • Youichi Yanase

    • Kyoto University
    • Department of Physics, Kyoto University