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Full-field diffraction-contrast imaging for electronic and magnetic order in quantum materials and functional devices at APS-U

Kolloquium der Abteilung 2

Recent efforts have successfully leveraged a multitude of diffraction-contrast mechanisms to

establish a novel imaging modality for 2D and 3D quantum materials (QMs) research in

anticipation of coherence-enhanced sensitivity at post-brightness-upgrade Advanced Photon

Source (APS-U). While precision-x-ray diffraction is a mainstay probe of QMs, this new imaging technique called dark-field x-ray microscopy (DFXM) has proven to be indispensable, when physics on the ‘average’ is insufficient. In this talk some illustrative cases of DFXM are reviewed that include an observation of local actors influencing a magneto-structural phase transition and comprehensive imaging of a complex set of charge-density waves (CDWs) in a Kagome metal purported to break time-reversal symmetry as well as a 3D reconstruction of a CDW deep within a superconducting state. Furthermore, a novel 3D reconstruction approach based on a codedaperture technique born in x-ray astronomy implemented for a search, and subsequent discovery, of mesoscale ‘nematic’ waves in an iron-based superconductor is outlined. Finally, fundamental mechanisms in 2D neuromorphic devices based on metal-insulator transitions have been exposed by imaging of structural transitions via DFXM in operando. To conclude, a vision of multimodal DFXM technique at APS-U coupled with in situ nano-calorimetry and fiber-Bragg-grating based dilation measurements of chare/spin/orbital ordered QMs is sketched. Work performed at the Advanced Photon Source was supported by the DOE, under Contract No. DE-AC02-06CH11357.



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