Pressure-Induced Rotational Symmetry Breaking in URu${}_2$Si${}_2$

Abstract

Phase transitions and symmetry are intimately linked. Melting of ice, for example, restores translation invariance. The mysterious hidden order (HO) phase of URu${}_2$Si${}_2$ has, despite relentless research efforts, kept its symmetry breaking element intangible. Here we present a high-resolution x-ray diffraction study of the URu${}_2$Si${}_2$ crystal structure as a function of hydrostatic pressure. Below a critical pressure threshold $p_c\approx 3$ kbar, no tetragonal lattice symmetry breaking is observed even below the HO transition $T_{HO}=17.5$ K. For $p>p_c$, however, a pressure-induced rotational symmetry breaking is identified with an onset temperatures $T_{OR}\sim 100$ K. The emergence of an orthorhombic phase is found and discussed in terms of an electronic nematic order that appears unrelated to the HO, but with possible relevance for the pressure-induced antiferromagnetic (AF) phase. Existing theories describe the HO and AF phases through an adiabatic continuity of a complex order parameter. Since none of these theories predicts a pressure-induced nematic order, our finding adds an additional symmetry breaking element to this long-standing problem.

6 pages, 4 figures and supplemental materials

References in corpus (13)

• Rotational Symmetry Breaking in the Hidden-Order Phase of URu2Si2
• Gapped itinerant spin excitations account for missing entropy in the hidden order state of URu${}_2$Si${}_2$
• Emergent Rank-5 'Nematic' Order in URu2Si2
• Hastatic Order in URu2Si2
• Fermi surface instability at the hidden-order transition of URu2Si2
• Chirality density wave of the 'hidden order' phase in URu${}_2$Si${}_2$
• Direct observation of lattice symmetry breaking at the hidden-order transition in URu2Si2
• Antiferromagnetic critical pressure in URu2Si2 under hydrostatic conditions
• Field-induced spin-density wave beyond hidden order in URu2Si2
• Chemical pressure tuning of URu${}_2$Si${}_2$ via isoelectronic substitution of Ru with Fe
• High-Field Fermi Surface Properties in the Low Carrier Heavy Fermion Compound URu2Si2
• On the possibility to detect multipolar order in URu${}_2$Si${}_2$ by the electric quadrupolar transition of resonant elastic X-ray scattering
• Charge-Stripe Order and Superconductivity in $\mathrm{I}{\mathrm{r}}_{1-\mathrm{x}}\mathrm{P}{\mathrm{t}}_{\mathrm{x}}\mathrm{T}{\mathrm{e}}_2$

Cited by in corpus (9)

• Hidden order and beyond: an experimental-theoretical overview of the multifaceted behavior of URu${}_2$Si${}_2$
• Quantum-well states at the surface of the heavy-fermion superconductor URu${}_2$Si${}_2$
• Chiral charge as hidden order parameter in URu${}_2$Si${}_2$
• Local observation of linear-$T$ superfluid density and anomalous vortex dynamics in URu${}_2$Si${}_2$
• Electronic nematicity in URu2Si2 revisited
• 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${}_2$
• Collinear antiferromagnetic order in URu${}_2$Si${}_{2-x}$P${}_x$ revealed by neutron diffraction
• Unified Theory of Hastatic order and Antiferromagnetism in URu${}_2$Si${}_2$