Phase separation in iron chalcogenide superconductor Rb₀.₈₊xFe₁.₆₊ySe₂ as seen by Raman light scattering and band structure calculations
We report Raman light scattering in the phase separated superconducting single crystal Rb₀.₇₇Fe₁.₆₁Se₂ with Tc = 32 K over a wide temperature region 3–500 K. The observed phonon lines from the majority vacancy ordered Rb₂Fe₄Se₅ (245) antiferromagnetic phase with TN = 525 K demonstrate modest anomali...
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Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
2016
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| Zitieren: | Phase separation in iron chalcogenide superconductor Rb₀.₈₊xFe₁.₆₊ySe₂ as seen by Raman light scattering and band structure calculations / Yu. Pashkevich, V. Gnezdilov, P. Lemmens, T. Shevtsova, A. Gusev, K. Lamonova, D. Wulferding, S. Gnatchenko, E. Pomjakushina, K. Conder // Физика низких температур. — 2003. — Т. 42, № 6. — С. 628-643. — Бібліогр.: 72 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1862536594813091840 |
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| author | Pashkevich, Yu. Gnezdilov, V. Lemmens, P. Shevtsova, T. Gusev, A. Lamonova, K. Wulferding, D. Gnatchenko, S. Pomjakushina, E. Conder, K. |
| author_facet | Pashkevich, Yu. Gnezdilov, V. Lemmens, P. Shevtsova, T. Gusev, A. Lamonova, K. Wulferding, D. Gnatchenko, S. Pomjakushina, E. Conder, K. |
| citation_txt | Phase separation in iron chalcogenide superconductor Rb₀.₈₊xFe₁.₆₊ySe₂ as seen by Raman light scattering and band structure calculations / Yu. Pashkevich, V. Gnezdilov, P. Lemmens, T. Shevtsova, A. Gusev, K. Lamonova, D. Wulferding, S. Gnatchenko, E. Pomjakushina, K. Conder // Физика низких температур. — 2003. — Т. 42, № 6. — С. 628-643. — Бібліогр.: 72 назв. — англ. |
| collection | DSpace DC |
| container_title | Физика низких температур |
| description | We report Raman light scattering in the phase separated superconducting single crystal Rb₀.₇₇Fe₁.₆₁Se₂ with Tc = 32 K over a wide temperature region 3–500 K. The observed phonon lines from the majority vacancy ordered Rb₂Fe₄Se₅ (245) antiferromagnetic phase with TN = 525 K demonstrate modest anomalies in the frequency, intensity and halfwidth at the superconductive phase transition. We identify phonon lines from the minority compressed RbδFe₂Se₂ (122) conductive phase. The superconducting gap with dx₂₋y₂ symmetry has been detected in our spectra. In the range 0–600 cm–¹ we observe a weak but highly polarized B₁g-type backgroundwhich becomes well-structured upon cooling. A possible magnetic or multiorbital origin of this background is discussed. We argue that the phase separation in M₀.₈₊xFe₁.₆₊ySe₂ is of pure magnetic origin. It occurs below the Néel temperature when the magnetic moment of iron reaches a critical value. We state that there is a spacer between the majority 245 and minority 122 phases. Using ab initio spin-polarized band structure calculations we demonstrate that the compressed vacancy ordered Rb₂Fe₄Se₅ phase can be conductive and therefore may serve as a protective interface spacer between the purely metallic RbδFe₂Se₂ phase and the insulating Rb₂Fe₄Se₅ phase providing percolative Josephson-junction like superconductivity all throughout of Rb₀.₈₊xFe₁.₆₊ySe₂. Our lattice dynamics calculations show significant differences in the phonon spectra of the conductive and insulating Rb₂Fe₄Se₅ phases.
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| first_indexed | 2025-11-24T11:38:28Z |
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| id | nasplib_isofts_kiev_ua-123456789-129161 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 0132-6414 |
| language | English |
| last_indexed | 2025-11-24T11:38:28Z |
| publishDate | 2016 |
| publisher | Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України |
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| spelling | Pashkevich, Yu. Gnezdilov, V. Lemmens, P. Shevtsova, T. Gusev, A. Lamonova, K. Wulferding, D. Gnatchenko, S. Pomjakushina, E. Conder, K. 2018-01-16T17:00:30Z 2018-01-16T17:00:30Z 2016 Phase separation in iron chalcogenide superconductor Rb₀.₈₊xFe₁.₆₊ySe₂ as seen by Raman light scattering and band structure calculations / Yu. Pashkevich, V. Gnezdilov, P. Lemmens, T. Shevtsova, A. Gusev, K. Lamonova, D. Wulferding, S. Gnatchenko, E. Pomjakushina, K. Conder // Физика низких температур. — 2003. — Т. 42, № 6. — С. 628-643. — Бібліогр.: 72 назв. — англ. 0132-6414 https://nasplib.isofts.kiev.ua/handle/123456789/129161 We report Raman light scattering in the phase separated superconducting single crystal Rb₀.₇₇Fe₁.₆₁Se₂ with Tc = 32 K over a wide temperature region 3–500 K. The observed phonon lines from the majority vacancy ordered Rb₂Fe₄Se₅ (245) antiferromagnetic phase with TN = 525 K demonstrate modest anomalies in the frequency, intensity and halfwidth at the superconductive phase transition. We identify phonon lines from the minority compressed RbδFe₂Se₂ (122) conductive phase. The superconducting gap with dx₂₋y₂ symmetry has been detected in our spectra. In the range 0–600 cm–¹ we observe a weak but highly polarized B₁g-type backgroundwhich becomes well-structured upon cooling. A possible magnetic or multiorbital origin of this background is discussed. We argue that the phase separation in M₀.₈₊xFe₁.₆₊ySe₂ is of pure magnetic origin. It occurs below the Néel temperature when the magnetic moment of iron reaches a critical value. We state that there is a spacer between the majority 245 and minority 122 phases. Using ab initio spin-polarized band structure calculations we demonstrate that the compressed vacancy ordered Rb₂Fe₄Se₅ phase can be conductive and therefore may serve as a protective interface spacer between the purely metallic RbδFe₂Se₂ phase and the insulating Rb₂Fe₄Se₅ phase providing percolative Josephson-junction like superconductivity all throughout of Rb₀.₈₊xFe₁.₆₊ySe₂. Our lattice dynamics calculations show significant differences in the phonon spectra of the conductive and insulating Rb₂Fe₄Se₅ phases. This paper is devoted to the memory of academician Kirill
 Borisovich Tolpygo — prominent Physicist, Teacher and Citizen,
 who made a great contribution to the lattice dynamics
 theory and many other branches of solid state physics.
 Authors thanks to Vladimir Pomjakushin for useful discussions.
 This work was supported in part by the State
 Fund of Fundamental Research of Ukraine and by the
 Ukrainian-Russian Grant No. 9-2010, NTH school Contacts
 in Nanosystems, and DFG. The calculations have
 been supported by resources of Ukrainian National GRID
 under NASU Grant No. 232. Yu. Pashkevich acknowledges
 partial support from the Swiss National Science Foundation
 (grant SNSF IZKOZ2 134161). en Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України Физика низких температур К 100-летию со дня рождения К.Б. Толпыго Phase separation in iron chalcogenide superconductor Rb₀.₈₊xFe₁.₆₊ySe₂ as seen by Raman light scattering and band structure calculations Article published earlier |
| spellingShingle | Phase separation in iron chalcogenide superconductor Rb₀.₈₊xFe₁.₆₊ySe₂ as seen by Raman light scattering and band structure calculations Pashkevich, Yu. Gnezdilov, V. Lemmens, P. Shevtsova, T. Gusev, A. Lamonova, K. Wulferding, D. Gnatchenko, S. Pomjakushina, E. Conder, K. К 100-летию со дня рождения К.Б. Толпыго |
| title | Phase separation in iron chalcogenide superconductor Rb₀.₈₊xFe₁.₆₊ySe₂ as seen by Raman light scattering and band structure calculations |
| title_full | Phase separation in iron chalcogenide superconductor Rb₀.₈₊xFe₁.₆₊ySe₂ as seen by Raman light scattering and band structure calculations |
| title_fullStr | Phase separation in iron chalcogenide superconductor Rb₀.₈₊xFe₁.₆₊ySe₂ as seen by Raman light scattering and band structure calculations |
| title_full_unstemmed | Phase separation in iron chalcogenide superconductor Rb₀.₈₊xFe₁.₆₊ySe₂ as seen by Raman light scattering and band structure calculations |
| title_short | Phase separation in iron chalcogenide superconductor Rb₀.₈₊xFe₁.₆₊ySe₂ as seen by Raman light scattering and band structure calculations |
| title_sort | phase separation in iron chalcogenide superconductor rb₀.₈₊xfe₁.₆₊yse₂ as seen by raman light scattering and band structure calculations |
| topic | К 100-летию со дня рождения К.Б. Толпыго |
| topic_facet | К 100-летию со дня рождения К.Б. Толпыго |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/129161 |
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