Strongly-coupled quantum critical point in an all-in-all-out antiferromagnet

Abstract

Dimensionality and symmetry play deterministic roles in the laws of Nature. They are important tools to characterize and understand quantum phase transitions, especially in the limit of strong correlations between spin, orbit, charge, and structural degrees of freedom. Using newly-developed, high-pressure resonant x-ray magnetic and charge diffraction techniques, we have discovered a quantum critical point in Cd2Os2O7 as the all-in-all-out (AIAO) antiferromagnetic order is continuously suppressed to zero temperature and, concomitantly, the cubic lattice structure continuously changes from space group Fd-3m to F-43m. Surrounded by three phases of different time reversal and spatial inversion symmetries, the quantum critical region anchors two phase lines of opposite curvature, with striking departures from a mean-field form at high pressure. As spin fluctuations, lattice breathing modes, and quasiparticle excitations interact in the quantum critical region, we argue that they present the necessary components for strongly-coupled quantum criticality in this three-dimensional compound.

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Cited by in corpus (5)

• A continuous metal-insulator transition driven by spin correlations
• Approaching the quantum critical point in a highly-correlated all-in-all-out antiferromagnet
• Crossover from charge density wave stabilized antiferromagnetism to superconductivity in Nd${}_{1-x}$La${}_x$NiC${}_2$ compounds
• Spin and orbital dynamics through the metal-to-insulator transition in Cd${}_2$Os${}_2$O${}_7$ probed with high-resolution RIXS
• The Future of the Correlated Electron Problem