Bose-Einstein condensate of Dirac magnons

ORAL

Abstract

A Dirac-like quasiparticle spectrum is generated for localized magnetic moments on a 2D honeycomb lattice. The bosonic nature of these excitations and pumping allow for an accumulation of Dirac bosons and open up the possibility of the Bose-Einstein condensation at the Dirac point.

We explore the formation and collective modes of the Bose-Einstein condensate of Dirac magnons (Dirac BEC). We derive a phenomenological multi-component model of pumped bosons together with bosons residing at Dirac nodes and study the dynamics of the condensates. The condensate coherence and its multi-component nature are manifested in the Rabi oscillations whose period is determined by a Haldane-like gap in the spin-wave spectrum. This gap also allows one to control the properties and stability of the collective modes.

A Dirac magnon BEC remains yet to be experimentally realized. We hope that our findings will stimulate the corresponding experimental search.

*We acknowledge support from the University of Connecticut, VILLUM FONDEN via the Centre of Excellence for Dirac Materials (Grant No. 11744), the European Research Council under the European Union Seventh Framework ERS-2018-SYG 810451 HERO, the Knut and Alice Wallenberg Foundation KAW 2018.0104, and the Deutsche Forschungsgemeinschaft DFG-TRR 80.

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Presenters

  • Pavlo Sukhachov

    • Department of Physics, Yale University
    • Yale University

Authors

  • Pavlo Sukhachov

    • Department of Physics, Yale University
    • Yale University

  • Saikat Banerjee

    • Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg
    • Univ Augsburg
    • University of Augsburg

  • Alexander Balatsky

    • Physics, University of Connecticut
    • Department of Physics, University of Connecticut
    • Department of Physics, University of Connecticut (UCONN)
    • University of Connecticut