3D visualizations of nanoscale phase separation and ultrafast dynamic correlation between phases in (Na0.32K0.68)0.95Fe1.75Se2
| Autor: | Kaung-Hsiung Wu, Jenh-Yih Juang, M. Liu, A. I. Boltalin, A. N. Vasiliev, Y. J. Chu, J. Whittaker, Igor Morozov, Jiunn-Yuan Lin, P. C. Cheng, Wen-Yen Tzeng, A. A. Zhukov, Chih-Wei Luo |
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| Rok vydání: | 2019 |
| Předmět: |
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 |
| Zdroj: | Physical Review Materials. 3 |
| ISSN: | 2475-9953 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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