Superconductivity at 31 K in the “111”-type iron arsenide superconductor Na1-xFeAs induced by pressureS. J. Zhang1, X. C. Wang1, Q. Q. Liu1, Y. X. Lv1, X. H. Yu1, 2, Z. J. Lin2, Y. S. Zhao2, L. Wang3, Y. Ding3, H. K. Mao3 and C. Q. Jin1
1 Institute of Physics, Chinese Academy of Sciences - Beijing 100190, China
2 LANSCE, Los Alamos National Laboratory - Los Alamos, NM 87545, USA
3 HPCAT, Geophysical Laboratory, Carnegie Institution of Washington - Argonne, IL 60439, USA
received 3 June 2009; accepted in final form 2 November 2009; published November 2009
published online 2 December 2009
The effect of pressure on the superconductivity of “111”-type Na1-xFeAs is investigated through temperature-dependent electrical-resistance measurements in a diamond anvil cell. The superconducting transition temperature (Tc) increases from 26 K to a maximum of 31 K as the pressure increases from ambient pressure to 3 GPa. Further increasing pressure suppresses Tc drastically. The behavior of pressure-tuned Tc in Na1-xFeAs is much different from that in LixFeAs, although they have the same Cu2Sb-type structure.
74.20.Mn - Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.).
74.62.Fj - Pressure effects.
74.25.Dw - Superconductivity phase diagrams.
© EPLA 2009