Small polaron formation in 5d spin-orbit coupled omsates

ORAL

Abstract

Small polarons (SP) have been thoroughly investigated in 3d transition metal oxides [1]. However, very little is known about these quasi-particles in 5d systems, since the more delocalised nature of the 5d orbitals reduces the strength of the Electronic Correlation (EC), making SP formation in these compounds rather unexpected. The spin-orbit coupled Dirac-Mott insulator Ba2NaOsO6 (BNOO) represents a candidate material for enabling polaron formation in a relativistic background, due to the relatively large EC (U ~ 3 eV) and Jahn-Teller activity [2]. We verify this hypothesis by combining first principles calculations with nuclear magnetic resonance (NMR) and muons measurements. We find that excess electrons injected into BNOO through chemical doping are trapped in Os sites and distort the local phonon field, typical hallmark of SP formation. SP are subjected to thermally activated hopping, revealed by anomalous peaks in the spin-lattice and spin-spin relaxation rates, attributed to fluctuation of the electric field gradients driven by a charge-related time dependent perturbation.

References

[1] C. Franchini et al., Nat. Rev. Mater., 1-27 (2021) 10.1038/s41578-021-00289-w.

[2] D. Fiore Mosca et al., Phys. Rev. B 103, 104401 (2021) 10.1103/PhysRevB.103.104401.

*University of Vienna

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Presenters

  • Lorenzo Celiberti

    • University of Vienna, A-1090 Vienna, Austria

Authors

  • Lorenzo Celiberti

    • University of Vienna, A-1090 Vienna, Austria

  • Dario Fiore Mosca

    • University of Vienna & Vienna Doctoral School of Physics
    • University of Vienna, A-1090 Vienna, Austria

  • Anna Tassetti

    • Alma Mater Studiorum–Università di Bologna, Bologna, 40127, Italy

  • Paola Caterina Forino

    • Alma Mater Studiorum–Università di Bologna, Bologna, 40127, Italy

  • Roberto De Renzi

    • University of Parma
    • University of Parma, 43124 Parma, Italy

  • Giuseppe Allodi

    • University of Parma
    • University of Parma, 43124 Parma, Italy

  • Vesna F Mitrovic

    • Brown University
    • Brown University, Providence, Rhode Island 02912, USA

  • Erick Garcia

    • Brown University
    • Brown University, Providence, Rhode Island 02912, USA

  • Rong Cong

    • Brown University
    • Brown University, Providence, Rhode Island 02912, USA

  • Patrick Woodward

    • The Ohio State University, Columbus, Ohio 43210, USA

  • Samuele Sanna

    • Univ of Bologna
    • Alma Mater Studiorum–Università di Bologna, Bologna, 40127, Italy
    • University of Bologna

  • Cesare Franchini

    • University of Vienna
    • Univ of Vienna
    • Univ of Vienna, Univ of Bologna
    • Universita' di Bologna & University of Vienna
    • University of Vienna, A-1090 Vienna, Austria, Alma Mater Studiorum–Università di Bologna, Bologna, 40127, Italy