Microscopic Theory of Spin Toroidization in Periodic Crystals

ORAL

Abstract

Spin toroidization has been proposed to be a primary order parameter in systems that break time reversal and inversion symmetry but preserve the combined symmetries. It has been related to various magnetoelectric phenomenon. However, previous theories of spin toroidization have been based on the multipole expansion in the electromagnetic theory, which is a classical theory by its nature. Here we provide a microscopic quantum-mechanical theory of spin toroidization in periodic crystals using Bloch functions. Our result is gauge invariant, and more importantly, it directly connects to the antisymmetric part of the spin magnetoelectric polarizability. To illustrate our result, we calculate the spin toroidization in a toy model and demonstrate that it is a genuine bulk property.

*This work is supported by DOE BES Grant DE-SC0012509 (Y.G. and D.X.) and
by NSF Grant DMR-1408838 (D.V.).

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Presenters

  • Yang Gao

    • Department of Physics, University of Texas at Austin
    • Department of Physics, Carnegie Mellon University

Authors

  • Yang Gao

    • Department of Physics, University of Texas at Austin
    • Department of Physics, Carnegie Mellon University

  • David Vanderbilt

    • Dept of Physics and Astronomy, Rutgers Univ
    • Physics, Rutgers Univ
    • Department of Physics and Astronomy, Rutgers University
    • Physics and Astronomy, Rutgers University
    • Physics and Astronomy, Rutgers Univiversity

  • Di Xiao

    • Carnegie Mellon University
    • Physics department, Carnegie Mellon University
    • Department of Physics, Carnegie Mellon University
    • Carnegie Mellon Univ