Intermittent dynamics of antiferromagnetic phase in inhomogeneous iron-based chalcogenide superconductor

Abstract

Coexistence of phases, characterized by different electronic degrees of freedom, commonly occurs in layered superconductors. Among them, alkaline intercalated chalcogenides are model systems showing microscale coexistence of paramagnetic (PAR) and antiferromagnetic (AFM) phases, however, temporal behavior of different phases is still unknown. Here, we report the first visualization of the atomic motion in the granular phase of K${}_x$Fe${}_{2-y}$Se${}_2$ using X-ray photon correlation spectroscopy. Unlike the PAR phase, the AFM texture reveals an intermittent dynamics with avalanches as in martensites. When cooled down across the superconducting transition temperature T${}_c$, the AFM phase goes through an anomalous slowing behavior suggesting a direct relationship between the atomic motions in the AFM phase and the superconductivity. In addition of providing a compelling evidence of avalanche-like dynamics in a layered superconductor, the results provide a basis for new theoretical models to describe quantum states in inhomogeneous solids.

6 pages, 3 figures

References in corpus (12)

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• Transport properties of the new Fe-based superconductor KxFe2Se2 (Tc = 33 K)
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• Temperature dependence of iron local magnetic moment in phase-separated superconducting chalcogenide
• Direct Observation of Microstructures on Superconducting Single Crystals of K${}_x$Fe${}_{2-y}$Se${}_2$
• Dislocations as a boundary between charge density wave and oxygen rich phases in a cuprate high temperature superconductor
• Suppression of the antiferromagnetic order when approaching the superconducting state in a phase-separated crystal of K${}_x$Fe${}_{2-y}$Se${}_2$

Cited by in corpus (2)

• Structural, magnetic, and electronic evolution of the spin-ladder system BaFe${}_2$S${}_{3-x}$Se${}_x$ with isoelectronic substitution
• Real-space observation of emergent complexity of phase evolution in micrometer-sized IrTe${}_2$ crystals