Hidden order and beyond: an experimental-theoretical overview of the multifaceted behavior of URu${}_2$Si${}_2$

Abstract

This Topical Review describes the multitude of unconventional behaviors in the hidden order, heavy fermion, antiferromagnetic and superconducting phases of the intermetallic compound URu${}_2$Si${}_2$ when tuned with pressure, magnetic field, and substitutions for all three elements. Such `perturbations' result in a variety of new phases beyond the mysterious hidden order that are only now being slowly understood through a series of state-of-the-science experimentation, along with an array of novel theoretical approaches. Despite all these efforts spanning more than 30 years, hidden order (HO) remains puzzling and non-clarified, and the search continues in 2019 into a fourth decade for its final resolution. Here we attempt to update the present situation of URu${}_2$Si${}_2$ importing the latest experimental results and theoretical proposals. First, let us consider the pristine compound as a function of temperature and report the recent measurements and models relating to its heavy Fermi liquid crossover, its HO and superconductivity (SC). Recent experiments and theories are surmized that address four-fold symmetry breaking (or nematicity), Isingness and unconventional excitation modes. Second, we review the pressure dependence of URu${}_2$Si${}_2$ and its transformation to antiferromagnetic long-range order. Next we confront the dramatic high magnetic-field phases requiring fields above 40 T. And finally, we attempt to answer how does random substitutions of other $5f$ elements for U, and $3d$, $4d$, and $5d$ elements for Ru, and even P for Si affect and transform the HO. Commensurately, recent theoretical models are summarized and then related to the intriguing experimental behavior.

75 pages, 27 figures. J. Phys.: Condensed Matter, in press

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• Lattice dynamics of the heavy fermion compound URu${}_2$Si${}_2$
• Multipole order and global/site symmetry in the hidden order phase of URu2Si2
• On the possibility to detect multipolar order in URu${}_2$Si${}_2$ by the electric quadrupolar transition of resonant elastic X-ray scattering
• Detailed optical spectroscopy of the hybridization gap and the hidden order transition in high quality URu${}_2$Si${}_2$ single crystals
• Electronic structure of ThRu2Si2 studied by angle-resolved photoelectron spectroscopy: Elucidating the contribution of U 5f states in URu2Si2
• Thermodynamic Measurement of Angular Anisotropy at the Hidden Order Transition of URu${}_2$Si${}_2$
• Electronic properties of a heavy-fermion U(Ru0.92Rh0.08)2Si2 single crystal
• Exceptional Ising Magnetic Behavior of Itinerant Spin-polarized Carriers in URu2Si2
• Neutron Scattering Study of URu${}_{2-x}$Re${}_x$Si${}_2$ with $x$ = 0.10: Driving Order towards Quantum Criticality
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• NMR Investigation of antiferromagnetism and coherence in URu${}_2$Si${}_{2-x}$P${}_x$
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• URu2Si2: hidden order and amplitude of quantum oscillations
• Hidden valence transition in URu2Si2?

Cited by in corpus (32)

• Synchrotron Radiation Techniques and their Application to Actinide Materials
• Chiral singlet superconductivity in the weakly correlated metal LaPt3P
• Unconventional fully-gapped superconductivity in the heavy-fermion metal CeCu${}_2$Si${}_2$
• Untangling the structural, magnetic dipole, and charge multipolar orders in Ba${}_2$MgReO${}_6$
• Advances in actinide thin films: synthesis, properties, and future directions
• Unusual Nonmagnetic Ordered State in CeCoSi Revealed by ${}^{59}$Co-NMR and NQR Measurements
• Nonlinear Magnetoelectric Effect under Magnetic Octupole Order: Its Application to a $d$-Wave Altermagnet and a Pyrochlore Lattice with All-In/All-Out Magnetic Order
• Chiral charge as hidden order parameter in URu${}_2$Si${}_2$
• Hidden orders in spin-orbit entangled correlated insulators
• Hidden Charge Order in an Iron Oxide Square-Lattice Compound
• Nature of the unconventional heavy fermion Kondo state in monolayer CeSiI
• Magnetic field-Temperature Phase Diagram of CeCoSi Constructed by Specific Heat, Magnetoresistivity, and Magnetization Measurements for a Single Crystal
• Kondo quasiparticle dynamics observed by resonant inelastic x-ray scattering
• Specific heat of CeRhIn${}_5$ in high magnetic fields: Magnetic phase diagram revisited
• Quantifying the U $5f$ covalence and degree of localization in U intermetallics
• Strain-induced long-range charge-density wave order in the optimally doped Bi${}_2$Sr${}_{2-x}$La${}_x$CuO${}_6$ superconductor
• Phonon-driven multipolar dynamics in a spin-orbit coupled Mott insulator
• Thermodynamic formulation of the spin magnetic octupole moment in bulk crystals
• Dipolar-octupolar correlations and hierarchy of exchange interactions in Ce${}_2$Hf${}_2$O${}_7$
• Global perspectives of the bulk electronic structure of URu${}_2$Si${}_2$ from angle-resolved photoemission
• Fe substitution in URu${}_2$Si${}_2$: singlet magnetism in an extended Doniach phase diagram
• In-plane anisotropic response to the uniaxial pressure in the hidden order state of URu${}_2$Si${}_2$
• Analysis of Magnetoacoustic Quadrupole Resonance and Application to Probe Quadrupole Degrees of Freedom in Quantum Magnets
• Symmetry Aspects of Chiral Superconductors
• Heat capacity of URu${}_{2-x}$Os${}_x$Si${}_2$ at low temperatures
• Structure-Driven Prediction of Magnetic Order in Uranium Compounds
• Polarized Neutron Diffraction Study on UPt${}_2$Si${}_2$
• Chiral superfluid helium-3 in the quasi-two-dimensional limit
• Collinear antiferromagnetic order in URu${}_2$Si${}_{2-x}$P${}_x$ revealed by neutron diffraction
• Proximity-induced hidden order transition in a correlated heterostructure Sr${}_2$VO${}_3$FeAs
• Quasi-two-dimensional Fermi surfaces of the antiferromagnet U${}_2$RhIn${}_8$ revealed by de Haas-van Alphen measurements
• Large Kohn anomaly and phonon collapse induced by charge density wave in UPt${}_2$Si${}_2$