Li Yangmu, Tabis W, Tang Y, Yu G, Jaroszynski J, Barišić N, Greven M
School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA.
AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, 30-059 Krakow, Poland.
Sci Adv. 2019 Feb 1;5(2):eaap7349. doi: 10.1126/sciadv.aap7349. eCollection 2019 Feb.
After three decades of intensive research attention, the emergence of superconductivity in cuprates remains an unsolved puzzle. One major challenge has been to arrive at a satisfactory understanding of the unusual metallic "normal state" from which the superconducting state emerges upon cooling. A second challenge has been to achieve a unified understanding of hole- and electron-doped compounds. Here, we report detailed magnetoresistance measurements for the archetypal electron-doped cuprate Nd Ce CuO that, in combination with previous data, provide crucial links between the normal and superconducting states and between the electron- and hole-doped parts of the phase diagram. The characteristics of the normal state (magnetoresistance, quantum oscillations, and Hall coefficient) and those of the superconducting state (superfluid density and upper critical field) consistently indicate two-band (electron and hole) features and point to hole pocket-driven superconductivity in these nominally electron-doped materials. We show that the approximate Uemura scaling between the superconducting transition temperature and the superfluid density found for hole-doped cuprates also holds for the small hole component of the superfluid density in electron-doped cuprates.
在经过三十年的深入研究关注之后，铜酸盐中超导性的出现仍然是一个未解之谜。一个主要挑战在于要对不寻常的金属“正常态”达成令人满意的理解，在冷却时超导态从该正常态中出现。第二个挑战是要对空穴掺杂和电子掺杂的化合物实现统一理解。在此，我们报告了对典型电子掺杂铜酸盐Nd Ce CuO进行的详细磁阻测量，这些测量结果与先前的数据相结合，在正常态与超导态之间以及相图的电子掺杂部分和空穴掺杂部分之间提供了关键联系。正常态的特性（磁阻、量子振荡和霍尔系数）以及超导态的特性（超流密度和上临界场）一致表明存在双带（电子和空穴）特征，并指向这些名义上电子掺杂材料中由空穴口袋驱动的超导性。我们表明，对于空穴掺杂铜酸盐所发现的超导转变温度与超流密度之间的近似上村标度关系，对于电子掺杂铜酸盐中超流密度的小空穴成分也成立。
