Dipartimento di Fisica, Politecnico di Torino, 10129 Torino, Italy.
Phys Rev Lett. 2010 Dec 3;105(23):237002. doi: 10.1103/PhysRevLett.105.237002. Epub 2010 Dec 2.
Directional point-contact Andreev-reflection measurements in Ba(Fe(1-x)Co(x))2As2 single crystals (T(c) = 24.5 K) indicate the presence of two superconducting gaps with no line nodes on the Fermi surface. The point-contact Andreev-reflection spectra also feature additional structures related to the electron-boson interaction, from which the characteristic boson energy Ω(b)(T) is obtained, very similar to the spin-resonance energy observed in neutron scattering experiments. Both the gaps and the additional structures can be reproduced within a three-band s ± Eliashberg model by using an electron-boson spectral function peaked at Ω(0) = 12 meV ≃ Ω(b)(0).
在 Ba(Fe(1-x)Co(x))2As2 单晶体（T(c) = 24.5 K）中进行的定向点接触安德烈夫反射测量表明，费米面不存在线节点，存在两个超导能隙。点接触安德烈夫反射谱还具有与电子-声子相互作用相关的附加结构，从中可以获得特征声子能量 Ω(b)(T)，非常类似于在中子散射实验中观察到的自旋共振能量。通过使用在 Ω(0) = 12 meV ≃ Ω(b)(0)处达到峰值的电子-声子谱函数，可以在三能带 s ± Eliashberg 模型内重现这些能隙和附加结构。
