论文标题
观察由高-TC超导体的干净CUO2保护的小费米口袋
Observation of small Fermi pockets protected by clean CuO2 sheets of a high-Tc superconductor
论文作者
论文摘要
高过渡温度（TC）的超导性发生在铜氧化物中，载体掺杂到抗铁磁（AF）Mott绝缘子。这一发现超过三十年前，立即导致了关于形成小费米口袋的预测。但是，尚未检测到这种结构，而它可能是将高-TC超导性与Mott物理学相关的关键要素。为了解决这个长期存在的问题，我们研究了五层BA2CA4CU5O10（F，O）2的电子结构，其内部CUO2平面在铜层中表现出最干净。最令人惊讶的是，我们发现通过角度分辨光发射光谱（ARPES）和量子振荡测量值一致地周围（PI/2，PI/2）闭合（PI/2，PI/2）。 D波超导间隙沿着口袋打开，揭示了同一CUO2纸中超导性和AF顺序之间的共存。我们的数据进一步表明，超导性可以发生，而无需来自抗焦点区域附近的州的贡献，这些州与其他竞争激励（例如电荷密度波（CDW）和伪gap状态）共享。这将对理解铜酸盐中的超导性和困惑的费米弧现象具有重要意义。
The superconductivity of high transition temperature (Tc) occurs in copper oxides with carrier-doping to an antiferromagnetic (AF) Mott insulator. This discovery more than thirty years ago immediately led to a prediction about the formation of a small Fermi pocket. This structure, however, has not yet been detected, while it could be a key element in relating high-Tc superconductivity to Mott physics. To address this long-standing issue, we investigate the electronic structure of a five-layered Ba2Ca4Cu5O10(F,O)2 with inner CuO2 planes demonstrated to be cleanest ever in cuprates. Most surprisingly, we find small Fermi surface (FS) pockets closed around (pi/2,pi/2) consistently by angle-resolved photoemission spectroscopy (ARPES) and quantum oscillation measurements. The d-wave superconducting gap opens along the pocket, revealing the coexistence between the superconductivity and AF order in the same CuO2 sheet. Our data further indicate that the superconductivity can occur without contribution from the states near the antinodal region, which are shared by other competing excitations such as the charge density wave (CDW) and pseudogap states. This will have significant implications for understanding the superconductivity and puzzling Fermi arc phenomena in cuprates.
