Raman scattering study on the hidden order and antiferromagnetic phases in URu$_{2-x}$Fe$_x$Si$_2$

ORAL

Abstract

The heavy fermion compound URu$_2$Si$_2$ possesses an unusual ground state known as the ``hidden order'' (HO) phase below $T=17.5$\,K, which evolves into an large moment antiferromagnetic (LMAFM) phase under pressure. A recent Raman scattering study shows that an $A_{2g}$ symmetry ($D_{4h}$) in-gap mode emerges in the HO phase, characterizing the excitation from a chirality density wave\footnote{H. Kung, R.E. Baumbach, E.D. Bauer, V.K. Thorsmolle, W. Zhang, K. Haule, J.A. Mydosh and G. Blumberg \textit{Science} \textbf{347}, 1339 (2015)}. Here, we report Raman scattering results for single crystal URu$_{2-x}$Fe$_x$Si$_2$ with $x\leq 0.2$, where the Fe substitution acts as chemical pressure, shifting the system's ground state from HO to LMAFM. We found that the $A_{2g}$ mode softens with doping, vanishes at the HO and LMAFM phase boundary, then re-emerges and hardens with doping in the LMAFM phase. The relations between the $A_{2g}$ mode energy and the strength of the HO/LMAFM order parameters will be discussed in this talk.

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Authors

  • Hsiang-Hsi Kung

    Rutgers University, Department of Physics \& Astronomy, Rutgers University

  • Sheng Ran

    University of California San Diego, University of California, San Diego

  • Noravee Kanchanavatee

    University of California San Diego

  • Alexander Lee

    Rutgers University, Department of Physics \& Astronomy, Rutgers University

  • Viktor Krapivin

    Rutgers University

  • Kristjan Haule

    RCEM, Rutgers Univ, Rutgers University, Dept. Physics, Rutgers University, Rutgers, The State University of New Jersey

  • M. B. Maple

    UC San Diego, Department of Physics and Center for Advanced Nanoscience, University of California, San Diego, USA, University of California San Diego, University of California, San Diego, University of California, San Diego, La Jolla, CA

  • Girsh Blumberg

    Rutgers University, Department of Physics \& Astronomy, Rutgers University, Rutgers Univ