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Quadrupolar fluctuations of heavy-fermion metal YbRu<sub>2</sub>Ge<sub>2</sub>

ORAL

Abstract

Long-range order of electric quadrupole moments is one characteristic phenomenon in the family of multipolar Kondo systems. The heavy-fermion metal YbRu2Ge2 enters a ferro-quadrupolar (FQ) phase below TFQ=10K, in which the B1g-symmetry quadrupole moments at Yb3+ sites order at zero wave vector [Proc. Natl. Acad. Sci. U.S.A. 116, 7232 (2019)]. This FQ phase is a realization of electronic nematic states since the electronic properties spontaneously break the four-fold rotational symmetry of the tetragonal crystal. We study the quadrupolar fluctuations of this compound by Raman scattering [Phys. Rev. B 99, 235104 (2019)]. The electronic Raman susceptibility in quadrupolar symmetry channels exhibit nearly Curie-law behavior, indicating weak exchange interactions between local quadrupoles. It is the relatively strong coupling between the quadrupole moments and the lattice strain fields in the B1g symmetry channel, analogous to cooperative Jahn-Teller effect, that enhances the vanishingly small Weiss temperature to the temperature of quadrupolar phase transition at TFQ.

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Presenters

  • Girsh Blumberg

    Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University-New Brunswick

Authors

  • Mai Ye

    Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University-New Brunswick

  • Elliott W Rosenberg

    Department of Applied Physics, Stanford University

  • Ian Fisher

    Stanford University, Stanford Univ, Department of Applied Physics and Geballe Laboratory for Advanced Materials, Stanford University, Geballe Laboratory for Advanced Materials & Dept. of Applied Physics, Stanford University, Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Geballe Laboratory for Advanced Materials, Stanford University, Department of Applied Physics, Stanford University

  • Girsh Blumberg

    Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University-New Brunswick