Superconductivity in (NH 3 ) y Cs 0.4 FeSe
2013; American Physical Society; Volume: 88; Issue: 9 Linguagem: Inglês
10.1103/physrevb.88.094521
ISSN1550-235X
AutoresLu Zheng, Masanari Izumi, Yusuke Sakai, Ritsuko Eguchi, Hidenori Goto, Yasuhiro Takabayashi, Takashi Kambe, Taiki Onji, Shingo Araki, Tatsuo C. Kobayashi, Jung-Eun Kim, Akihiko Fujiwara, Yoshihiro Kubozono,
Tópico(s)Rare-earth and actinide compounds
ResumoAlkali-metal-intercalated FeSe materials, (NH${}_{3}$)${}_{\mathrm{y}}$${M}_{0.4}$FeSe ($M$: K, Rb, and Cs), have been synthesized using the liquid NH${}_{3}$ technique. (NH${}_{3}$)${}_{\mathrm{y}}$Cs${}_{0.4}$FeSe shows a superconducting transition temperature (${T}_{\mathrm{c}}$) as high as 31.2 K, which is higher by 3.8 K than the ${T}_{\mathrm{c}}$ of nonammoniated Cs${}_{0.4}$FeSe. The ${T}_{\mathrm{c}}$s of (NH${}_{3}$)${}_{\mathrm{y}}$K${}_{0.4}$FeSe and (NH${}_{3}$)${}_{\mathrm{y}}$Rb${}_{0.4}$FeSe are almost the same as those of nonammoniated K${}_{0.4}$FeSe and Rb${}_{0.4}$FeSe. The ${T}_{\mathrm{c}}$ of (NH${}_{3}$)${}_{\mathrm{y}}$Cs${}_{0.4}$FeSe shows a negative pressure dependence. A clear correlation between ${T}_{\mathrm{c}}$ and lattice constant $c$ is found for ammoniated metal-intercalated FeSe materials, suggesting a correlation between Fermi-surface nesting and superconductivity.
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