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arXiv · 1712.02244

Formation of single-phase disordered CsxFe2-ySe2 at high pressure

V. Svitlyk·E. Pomjakushina·A. Krzton-Maziopa·K. Conder·M. Mezouar
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Abstract

A single-phase high pressure (HP) modification of CsxFe2-ySe2 was synthesized at 11.8 GPa at ambient temperature. Structurally this polymorph is similar to the minor low pressure (LP) superconducting phase, namely they both crystallize in a ThCr2Si2-type structure without ordering of the Fe vacancies within the Fe-deficient FeSe4 layers. The HP CsxFe2-ySe2 polymorph is found to be less crystalline and nearly twice as soft compared to the parent major and minor phases of CsxFe2-ySe2. It can be quenched to low pressures and is stable at least on the scale of weeks. At ambient pressure the HP polymorph of CsxFe2-ySe2 is expected to exhibit different superconducting properties compared to its LP minor phase (Tc = 27 K).

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V. Svitlyk, E. Pomjakushina, A. Krzton-Maziopa, K. Conder, M. Mezouar. 2018-06-15. Formation of single-phase disordered CsxFe2-ySe2 at high pressure. https://doi.org/10.1103/physrevb.97.214512

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