Nanoscale spectroscopic imaging of phase separation in a correlated material by resonant X-ray holography

Abstract

Nanoscale phase coexistence and inhomogeneity are ubiquitous in correlated electron materials, existing in doped Mott insulators, manganites, and high-temperature superconductors. The small length scales and lack of contrast mechanisms make it extremely challenging to measure real-space images of the phase coexistence with high resolution. Yet, images aid our understanding of how phase coexistence and domain boundaries dictate the exotic material properties. Here we show that resonant soft-X-ray holography, previously employed to image magnetic domains, can be used to image phase separation on the nanoscale. We observe nucleation and growth of nanometre-sized metallic domains out of the insulating phase of the prototypical correlated material VO2, using linearly polarized coherent synchrotron radiation. By spectrally resolving the holograms, we extract differential soft X-ray absorption spectra with 50 nm spatial resolution. Furthermore, when combined with ultra-bright and ultra-short X-ray sources, X-ray holography could capture both nanoscale spatial variations and temporal fluctuations that occur close to the transition temperatures or are induced by femtosecond light pulses that cannot be observed with alternative imaging methods.

4 pages 4 figures

References in corpus (7)

• Mott transition in VO2 revealed by infrared spectroscopy and nano-imaging
• Orbital-assisted metal-insulator transition in VO${}_2$
• Inhomogeneity of charge density wave order and quenched disorder in a high Tc superconductor
• VO2: A Novel View from Band Theory
• Direct Observation of Decoupled Structural and Electronic Transitions and an Ambient Pressure Monoclinic-Like Metallic Phase of VO${}_2$
• Photoemission evidence for crossover from Peierls-like to Mott-like transition in highly strained VO${}_2$
• Phase separation in doped Mott insulators

Cited by in corpus (7)

• Ultrafast X-ray imaging of the light-induced phase transition in VO2
• Does VO${}_2$ Host a Transient Monoclinic Metallic Phase?
• Nanoscale-femtosecond dielectric response of Mott insulators captured by two-colour near-field ultrafast electron microscopy
• Early-stage dynamics of metallic droplets embedded in the nanotextured Mott insulating phase of V${}_2$O${}_3$
• Mapping nanoscale charge states and phase domains with quantitative hyperspectral coherent diffractive imaging spectroscopy
• Multi-mode excitation drives disorder during the ultrafast melting of a C4-symmetry-broken phase
• Imaging ferroelectric domains with soft X-ray ptychography at the oxygen K-edge