Author:
Yang Yanxing,Zhang Hewei,Zhuang Haizheng
Abstract
Phonon anomalies have been reported in iron-pnictide superconductors indicating a diverse interplay between different orders in the materials. Here, we report Raman scattering measurements on Sr(Fe1–x
Co
x
)2As2 (x = 0 and x = 0.04) single crystals in the B
2g
symmetry with respect to a 1 Fe unit cell. Upon cooling, we observe a larger split (13 cm−1) of Eg
Raman phonon modes pertaining to in-plane Fe and As displacements as the crystals undergo the tetragonal-to-orthorhombic structural phase transition, although a considerable split (9 cm−1) has been reported in Ba(Fe1–x
Co
x
)2As2. Furthermore, the splitting of Eg
phonon modes is strongly reduced upon doping. We perform an order-parameter analysis revealing a similar doping dependence of Eg
phonon splitting as reported in other compounds of the 122 family, indicating these phonon anomalies widely exist in 122 iron-based superconductors and might share the same mechanisms.
Subject
General Physics and Astronomy