Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2
Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2
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Ba0.6K0.4Fe2As2 中费米面相关的无节点超导能隙的观测
DOI：
10.1209/0295-5075/83/47001
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发表时间：
2008-01-01
期刊：
影响因子：
1.8
通讯作者：
Wang, N. L.
中科院分区：
文献类型：
--
作者：
Ding, H.;Richard, P.;Wang, N. L.
我们对新发现的超导体Ba(0.6)K(0.4)Fe(2)As(2) （T(c) = 37 K）进行了高分辨率角分辨光电子能谱研究。我们观察到两个不同值的超导隙：在两个小的类空穴和类电子费米表面（FS）片上有一个大的隙（Delta类似于12 meV），在大的类空穴FS上有一个小的隙（类似于6meV）。这两个间隙在体转变温度（T(c)）同时闭合，在各自的FS片周围无节点且几乎各向同性。各向同性配对相互作用强烈依赖于轨道，因为比值2 δ /k(B)T(c)在不同波段从弱耦合切换到强耦合。在母化合物中，由（pi, 0）自旋密度波向量连接的两个小FS上，由于强配对而产生的相同且惊人的大超导隙强烈表明，配对机制源于这两个嵌套FS片之间的带间相互作用。版权所有中国人民解放军，2008。
We have performed a high-resolution angle- resolved photoelectron spectroscopy study on the newly discovered superconductor Ba(0.6)K(0.4)Fe(2)As(2) (T(c) = 37 K). We have observed two superconducting gaps with different values: a large gap (Delta similar to 12 meV) on the two small hole-like and electron-like Fermi surface (FS) sheets, and a small gap (similar to 6meV) on the large hole-like FS. Both gaps, closing simultaneously at the bulk transition temperature (T(c)), are nodeless and nearly isotropic around their respective FS sheets. The isotropic pairing interactions are strongly orbital dependent, as the ratio 2 Delta/k(B)T(c) switches from weak to strong coupling on different bands. The same and surprisingly large superconducting gap due to strong pairing on the two small FSs, which are connected by the (pi, 0) spin-density-wave vector in the parent compound, strongly suggests that the pairing mechanism originates from the inter-band interactions between these two nested FS sheets. Copyright (c) EPLA, 2008.