Complex order above the Kondo Coherence temperature in UPt2Si2 and UCr2Si2

ORAL

Abstract

For strongly correlated f-electron metals it is commonplace for exotic ordered states to occur at temperatures well below the Kondo coherence temperature. More unusual is for phase transitions to emerge from the incoherent f-electron lattice at elevated temperatures, where single ion Kondo physics and strong thermal fluctuations would naively be presumed to be dominant terms. This is despite the prevalence of structural/electronic instabilities in the isolated f-electron elements, where a leading example is plutonium which undergoes six structure changes and features novel behavior including negative thermal expansion in the delta phase. In this talk we will discuss results for two examples: UPt2Si2 and UCr2Si2. Both systems exhibit phase transitions near room temperature that may involve modulation of the lattice or charge density wave order. In addition, UCr2Si2 undergoes a structural phase transition near 210 K. We will focus on efforts to identify the order parameters for these phases.

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Presenters

  • Ryan Baumbach

    National High Magnetic Field Laboratory, Florida State University, Florida State University, NHMFL-FSU, National High Magnetic Field Laboratory, National High Magnetic Field Laboratory and Florida State University, National High Magnetic Field Laboratory - Florida State University, NHMFL

Authors

  • Ryan Baumbach

    National High Magnetic Field Laboratory, Florida State University, Florida State University, NHMFL-FSU, National High Magnetic Field Laboratory, National High Magnetic Field Laboratory and Florida State University, National High Magnetic Field Laboratory - Florida State University, NHMFL

  • You Lai

    National High Magnetic Field Laboratory, Florida State University, NHMFL-FSU, National High Magnetic Field Laboratory and Florida State University

  • Greta Chappell

    Florida State University, National High Magnetic Field Laboratory, National High Magnetic Field Laboratory and Florida State University

  • David E Graf

    National High Magnetic Field Laboratory, National High Magnetic Field Lab, Tallahassee, FL, National High Magnetic Field Laboratory and Department of Physics, Florida State University, National High Magnetic Field Lab, NHMFL, Tallahassee, FL, United States, Florida State University, National High Magnetic Field Laboratory, Florida State University, NHMFL-FSU, National High Magnetic Field Laboratory and Florida State University, NHMFL

  • Xin Yan

    National High Magnetic Field Laboratory and Florida State University

  • John A Mydosh

    Kammerlingh Onnes Laboratory and Institute Lorentz, Leiden University