Sizable Residual Quasiparticle Density of States Induced by Impurity Scattering Effect in Ba(Fe 1-x Co x ) 2 As 2 Single Crystals
Sizable Residual Quasiparticle Density of States Induced by Impurity Scattering Effect in Ba(Fe 1-x Co x ) 2 As 2 Single Crystals
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DOI：
10.1088/0256-307x/27/3/037402
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发表时间：
2010-03
影响因子：
3.5
通讯作者：
Mu Gang;Zeng Bin;Cheng Peng;Wang Zhao-Sheng;Fang Lei;Shen Bing;S. Lei;R. Cong;Wen Hai-hu
中科院分区：
文献类型：
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作者：
Mu Gang;Zeng Bin;Cheng Peng;Wang Zhao-Sheng;Fang Lei;Shen Bing;S. Lei;R. Cong;Wen Hai-hu
在宽掺杂范围内测量了Ba(Fe1-xCox)2As2单晶的低温比热Cp。在所有样品的低温极限都观察到了相当大的剩余比热系数γ0。还测定了T_c附近的比热跳跃，即ΔCp/T|\T_c。结果表明，-γ_0、Δ_p/T|\T和T_c与掺杂具有相似的演化规律。当考虑钴掺杂作为FeAs平面上的么正散射中心时，这些都可以在S±配对对称性模型中得到很好的解释。我们的结果揭示了FeAs超导体中杂质散射的重要影响。
Low-temperature specific heat Cp is measured on Ba(Fe1–xCox)2As2 single crystals in a wide doping region. A sizeable residual specific heat coefficient γ0 is observed in the low temperature limit of all samples. The specific heat jump near Tc, i.e. ΔCp/T|\Tc, is also determined. It is found that –γ0, ΔCP/T|\Tc and Tc all share a similar evolution with doping. These can be well understood within the model of S± pairing symmetry when accounting for the cobalt-dopants as unitary scattering centers in the FeAs planes. Our results reveal a non-trivial impact of impurity scattering in FeAs-based superconductors.