Contrasting spin dynamics between underdoped and overdoped Ba(Fe1-xCox)2As2.
We report the first NMR investigation of spin dynamics in the overdoped nonsuperconducting regime of Ba(Fe1-xCox)2As2 up to x=0.26. We demonstrate that the absence of interband transitions with large momentum transfer Q{AF} approximately (pi/a,0) between the hole and electron Fermi surfaces results in complete suppression of antiferromagnetic spin fluctuations for x greater than or approximately 0.15. Our experimental results provide direct evidence for a correlation between T{c} and the strength of Q{AF} antiferromagnetic spin fluctuations.
Ning
F L
FL
Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S4M1, Canada.
Ahilan
K
K
Imai
T
T
Sefat
A S
AS
McGuire
M A
MA
Sales
B C
BC
Mandrus
D
D
Cheng
P
P
Shen
B
B
Wen
H-H
HH