Electro-nuclear transition into a spatially modulated magnetic state in YbRh${}_2$Si${}_2$

Abstract

The nature of the antiferromagnetic order in the heavy fermion metal YbRh${}_2$Si${}_2$, its quantum criticality, and superconductivity, which appears at low mK temperatures, remain open questions. We report measurements of the heat capacity over the wide temperature range 180 $\mu$K - 80 mK, using current sensing noise thermometry. In zero magnetic field we observe a remarkably sharp heat capacity anomaly at 1.5 mK, which we identify as an electro-nuclear transition into a state with spatially modulated electronic magnetic order of maximum amplitude 0.1${\mu }_B$. We also report results of measurements in magnetic fields in the range 0 to 70 mT, applied perpendicular to the c-axis, which show eventual suppression of this order. These results demonstrate a coexistence of a large moment antiferromagnet with putative superconductivity.

12 pages, 14 figures, including the supplementary information

References in corpus (14)

• Quantum Criticality in Heavy Fermion Metals
• Theory of Intertwined Orders in High Temperature Superconductors
• Quantum criticality
• Heavy Fermions and Quantum Phase Transitions
• Quantum phases driven by strong correlations
• Multiple energy scales at a quantum critical point
• Emergence of superconductivity in the canonical heavy-electron metal YbRh2Si2
• Electron spin resonance in Kondo systems
• Superconductivity in an extreme strange metal
• Violation of critical universality at the antiferromagnetic phase transition of YbRh2Si2
• Cooling low-dimensional electron systems into the microkelvin regime
• Direct Observation of Collective Electronuclear Modes About a Quantum Critical Point
• Magnetization study of the energy scales in YbRh${}_2$Si${}_2$ under chemical pressure
• Limits to magnetic quantum criticality from nuclear spins

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