Open AccessQuantum critical point in SmO 1−x F x FeAs and oxygen vacancy induced by high fluorine dopant
Author(s) -
Cheng Jie,
Chu Shengqi,
Chu Wangsheng,
Xu Wei,
Zhou Jing,
Zhang Linjuan,
Zhao Haifeng,
Liu Ronghua,
Chen Xianhui,
Marcelli Augusto,
Wu Ziyu
Publication year - 2011
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049511026483
Subject(s) - dopant , fluorine , oxygen , vacancy defect , crystallographic defect , materials science , crystallography , work (physics) , atomic physics , chemistry , condensed matter physics , physics , doping , thermodynamics , quantum mechanics , metallurgy
The local lattice and electronic structure of the high‐ T c superconductor SmO 1– x F x FeAs as a function of F‐doping have been investigated by Sm L 3 ‐edge X‐ray absorption near‐edge structure and multiple‐scattering calculations. Experiments performed at the L 3 ‐edge show that the white line (WL) is very sensitive to F‐doping. In the under‐doped region ( x ≤ 0.12) the WL intensity increases with doping and then it suddenly starts decreasing at x = 0.15. Meanwhile, the trend of the WL linewidth versus F‐doping levels is just contrary to that of the intensity. The phenomenon is almost coincident with the quantum critical point occurring in SmO 1– x F x FeAs at x ≃ 0.14. In the under‐doped region the increase of the intensity is related to the localization of Sm‐ 5d states, while theoretical calculations show that both the decreasing intensity and the consequent broadening of linewidth at high F‐doping are associated with the content and distribution of oxygen vacancies.