Observation of small Fermi pockets protected by clean CuO2 sheets of a high-Tc superconductor
Observation of small Fermi pockets protected by clean CuO2 sheets of a high-Tc superconductor
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DOI：
10.1126/science.aay7311
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发表时间：
2020-08-14
期刊：
影响因子：
56.9
通讯作者：
Kondo, Takeshi
中科院分区：
文献类型：
--
作者：
Kunisada, So;Isono, Shunsuke;Kondo, Takeshi
在具有高临界转变温度（T-c）的铜氧化物超导体中，已经预测对作为反铁磁Mott绝缘体的母体化合物进行轻空穴掺杂会导致小费米口袋的形成。然而，这些口袋没有被观察到。在这里，我们研究了五层Ba 2Ca 4Cu 5 O 10（F，O）（2）的电子结构，它具有内部氧化铜（CuO 2）平面，具有极低的无序度，并通过角分辨光电子能谱和量子振荡测量发现小费米口袋集中在布里渊区的（pi/2，pi/2）。d波超导能隙沿着口袋打开，揭示了在同一个CuO 2片超导和反铁磁有序共存。这些数据进一步表明，超导性可以在没有（pi，0）附近的波腹区域的贡献的情况下发生，这是由其他竞争激发共享的。
In cuprate superconductors with high critical transition temperature (T-c), light hole-doping to the parent compound, which is an antiferromagnetic Mott insulator, has been predicted to lead to the formation of small Fermi pockets. These pockets, however, have not been observed. Here, we investigate the electronic structure of the five-layered Ba2Ca4Cu5O10(F,O)(2), which has inner copper oxide (CuO2) planes with extremely low disorder, and find small Fermi pockets centered at (pi/2, pi/2) of the Brillouin zone by angle-resolved photoemission spectroscopy and quantum oscillation measurements. The d-wave superconducting gap opens along the pocket, revealing the coexistence between superconductivity and antiferromagnetic ordering in the same CuO2 sheet. These data further indicate that superconductivity can occur without contribution from the antinodal region around (pi, 0), which is shared by other competing excitations.