Many researchers have pointed out that there is a quantum critical point (QCP) in the F-doped SmOFeAs system. In this paper, the electronic structure and local structure of the superconductive FeAs layer in SmO1-xFxFeAs as a function of the F-doping concentration have been investigated using Fe and As K-edge X-ray absorption spectroscopy. Experiments performed on the X-ray absorption near-edge structure showed that in the vicinity of the QCP the intensity of the pre-edge feature at the Fe-edge decreases continuously, while there is a striking rise of the shoulder-peak at the As edge, suggesting the occurrence of charge redistribution near the QCP. Further analysis on the As K-edge extended X-ray absorption fine structure demonstrated that the charge redistribution originates mostly from a shortening of the Fe-As bond at the QCP. An evident relationship between the mysterious QCP and the fundamental Fe-As bond was established, providing new insights on the interplay between QCP, charge dynamics and the local structural Fe-As bond in Fe-based superconductors.
Cheng, J,Dong, P,Xu, W,et al. Charge redistribution and a shortening of the Fe-As bond at the quantum critical point of SmO1- xFxFeAs[J]. JOURNAL OF SYNCHROTRON RADIATION,2015,22:1030-1034.
Cheng, J.,Dong, P.,Xu, W.,Liu, SL.,Chu, WS.,...&吴自玉.(2015).Charge redistribution and a shortening of the Fe-As bond at the quantum critical point of SmO1- xFxFeAs.JOURNAL OF SYNCHROTRON RADIATION,22,1030-1034.
Cheng, J,et al."Charge redistribution and a shortening of the Fe-As bond at the quantum critical point of SmO1- xFxFeAs".JOURNAL OF SYNCHROTRON RADIATION 22(2015):1030-1034.