Evidence for two energy scales in the superconducting state of optimally doped (Bi,Pb)2(Sr,La)2CuO6+delta.
Evidence for two energy scales in the superconducting state of optimally doped (Bi,Pb)2(Sr,La)2CuO6+delta.
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DOI：
10.1103/physrevlett.98.267004
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发表时间：
2006-11
影响因子：
8.6
通讯作者：
T. Kondo;T. Takeuchi;A. Kaminski;S. Tsuda;Shik Shin
中科院分区：
文献类型：
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作者：
T. Kondo;T. Takeuchi;A. Kaminski;S. Tsuda;Shik Shin
我们用角分辨光电子能谱研究了(Bi，Pb)_2(Sr，La)_2CuO_6+三角晶体的能隙(S)。我们发现，在超导状态下，光谱带隙有两个分量：超导带隙和伪带隙。它们在动量和温度依赖性上的差异表明它们代表了两个不同的能量尺度。节点附近的光谱显示一个尖锐的峰，在T(C)以下有一个小间隙，在T(C)处关闭。在反节点附近，光谱很宽，在T(C)上下有大约40 meV的大能隙。后者的谱形和带隙大小在T(C)上几乎是恒定的，这表明在T(C)以下，赝隙态与超导态共存，并且它主导着反节点附近的光谱。我们推测，在超导带隙最大的反节点区，赝隙态通过减小谱重来与超导竞争。
We use angle-resolved photoemission spectroscopy to investigate the energy gap(s) in (Bi,Pb)2(Sr,La)2CuO6+delta. We find that the spectral gap has two components in the superconducting state: a superconducting gap and pseudogap. Differences in their momentum and temperature dependence suggest that they represent two separate energy scales. Spectra near the node reveal a sharp peak with a small gap below T(c) that closes at T(c). Near the antinode, spectra are broad with a large energy gap of approximately 40 meV above and below T(c). The latter spectral shape and gap magnitude are almost constant across T(c), indicating that the pseudogap state coexists with the superconducting state below T(c), and it dominates spectra around the antinode. We speculate that the pseudogap state competes with the superconductivity by diminishing spectral weight in antinodal regions, where the superconducting gap is largest.