Electronic phase diagram of high-temperature copper oxide superconductors
Electronic phase diagram of high-temperature copper oxide superconductors
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DOI：
10.1073/pnas.1101008108
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发表时间：
2011-06-07
影响因子：
11.1
通讯作者：
Campuzano, J. C.
中科院分区：
文献类型：
--
作者：
Chatterjee, Utpal;Ai, Dingfei;Campuzano, J. C.
为了理解铜氧化物高温超导性的起源，我们必须理解它出现的正常状态。在这里，我们研究的正常状态下的电子激发的演变与温度和载流子浓度在Bi 2Sr 2CaCu 2 O 8 + δ使用角分辨光电发射。与常规超导体相比，其中存在将正常状态与超导状态分开的单一温度标度Tc，高温超导体表现出两个额外的温度标度。一个是赝能隙尺度T*，低于该尺度，电子激发表现出能隙。第二个是相干尺度T-coh，低于该尺度，由于激发的寿命增加而出现尖锐的光谱特征。我们发现，T* 和T-coh是强烈的掺杂依赖性和交叉彼此附近的最佳掺杂。因此，最高的超导Tc出现在一个不寻常的正常状态，其特征是具有能隙的相干激发。
In order to understand the origin of high-temperature superconductivity in copper oxides, we must understand the normal state from which it emerges. Here, we examine the evolution of the normal state electronic excitations with temperature and carrier concentration in Bi2Sr2CaCu2O8+delta using angle-resolved photo-emission. In contrast to conventional superconductors, where there is a single temperature scale T-c separating the normal from the superconducting state, the high-temperature superconductors exhibit two additional temperature scales. One is the pseudogap scale T*, below which electronic excitations exhibit an energy gap. The second is the coherence scale T-coh, below which sharp spectral features appear due to increased lifetime of the excitations. We find that T* and T-coh are strongly doping dependent and cross each other near optimal doping. Thus the highest superconducting T-c emerges from an unusual normal state that is characterized by coherent excitations with an energy gap.