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3D visualizations of nanoscale phase separation and ultrafast dynamic correlation between phases in (Na0.32K0.68)0.95Fe1.75Se2
- Source :
- Physical Review Materials. 3
- Publication Year :
- 2019
- Publisher :
- American Physical Society (APS), 2019.
-
Abstract
- Phase separation of metallic and antiferromagnetic (AFM) insulating phases in alkaline iron selenides $({\mathrm{A}}_{x}\mathrm{F}{\mathrm{e}}_{2\ensuremath{-}y}\mathrm{S}{\mathrm{e}}_{2})$ continues to attract intense interest because the relationship between two peculiar features probably is a key to clarifying the pairing mechanism of ${\mathrm{A}}_{x}\mathrm{F}{\mathrm{e}}_{2\ensuremath{-}y}\mathrm{S}{\mathrm{e}}_{2}$ superconductors. Here we report that the three-dimensional (3D) visualizations of nanoscale phase separation in ${(\mathrm{N}{\mathrm{a}}_{0.32}{\mathrm{K}}_{0.68})}_{0.95}\mathrm{F}{\mathrm{e}}_{1.75}\mathrm{S}{\mathrm{e}}_{2}$ single crystals are revealed by hybrid focused-ion-beam scanning electron microscopy and the superconducting paths are fully percolative in 3D. Moreover, the phase-related ultrafast dynamics in ${(\mathrm{N}{\mathrm{a}}_{0.32}{\mathrm{K}}_{0.68})}_{0.95}\mathrm{F}{\mathrm{e}}_{1.75}\mathrm{S}{\mathrm{e}}_{2}$ is studied by dual-color pump-probe spectroscopy. The anomalous changes in the electron and acoustic phonon components of transient reflectivity change $(\mathrm{\ensuremath{\Delta}}R/R)$ identify two characteristic temperatures ${T}^{*}\ensuremath{\sim}100\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ (the onset temperature of coupling between the nanometallic and AFM phases) and ${T}_{\mathrm{H}}\ensuremath{\sim}230\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ (the onset temperature of the metallic-interface phase). An energy-transfer channel between the nanometallic and AFM phases is inferred. This proposed channel provides insight into the pairing mechanism of alkaline iron selenide superconductors.
- Subjects :
- Superconductivity
Materials science
Physics and Astronomy (miscellaneous)
Atomic force microscopy
02 engineering and technology
021001 nanoscience & nanotechnology
Coupling (probability)
01 natural sciences
Reflectivity
Crystallography
Phase (matter)
0103 physical sciences
Antiferromagnetism
General Materials Science
010306 general physics
0210 nano-technology
Nanoscopic scale
Subjects
Details
- ISSN :
- 24759953
- Volume :
- 3
- Database :
- OpenAIRE
- Journal :
- Physical Review Materials
- Accession number :
- edsair.doi...........3a54e5780f0d5eb8f3f4132b075f97fc
- Full Text :
- https://doi.org/10.1103/physrevmaterials.3.034802