Abstract
We present a 77Se NMR study of the newly discovered iron selenide superconductor KyFe2-xSe2 , in which Tc =32K. Below Tc , the Knight shift 77K drops sharply with temperature, providing strong evidence for singlet pairing. Above Tc , Korringa-type relaxation indicates Fermi-liquid behavior. Our experimental results set strict constraints on the nature of possible theories for the mechanism of high-Tc superconductivity in this iron selenide system.
Original language | English |
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Article number | 197001 |
Journal | Physical Review Letters |
Volume | 106 |
Issue number | 19 |
Online published | 9 May 2011 |
DOIs | |
Publication status | Published - 13 May 2011 |
Externally published | Yes |