Microscopic annealing process and its impact on superconductivity in T′-structure electron-doped copper oxides
Microscopic annealing process and its impact on superconductivity in T′-structure electron-doped copper oxides
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DOI：
10.1038/nmat1847
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发表时间：
2007-03-01
期刊：
影响因子：
41.2
通讯作者：
Ando, Yoichi
中科院分区：
文献类型：
--
作者：
Kang, Hye Jung;Dai, Pengcheng;Ando, Yoichi
当空穴或电子被掺杂到其绝缘母体化合物的CuO 2平面中时，高转变温度的超导性出现在铜氧化物中。然而空穴掺杂在许多铜氧化物中快速诱导金属行为和超导性，在诸如R2CuO 4（R是Nd、Pr、La、Ce等）的材料中仅电子掺杂是不够的，其中需要在低氧环境中退火生长的样品以去除微量的氧以诱导超导性。在这里，我们表明，氧还原的微观过程中修复Cu缺陷的生长材料，并在化学计量的CuO 2平面中产生氧空位，有效地减少无序和提供巡回载体的超导性。这个长期存在的材料问题的解决表明，超导的基本机制对于电子和空穴掺杂的氧化铜是相同的。
High-transition-temperature superconductivity arises in copper oxides when holes or electrons are doped into the CuO2 planes of their insulating parent compounds. Whereas hole doping quickly induces metallic behaviour and superconductivity in many cuprates, electron doping alone is insuffcient in materials such as R2CuO4 (R is Nd, Pr, La, Ce and so on), where it is necessary to anneal an as grown sample in a low-oxygen environment to remove a tiny amount of oxygen in order to induce superconductivity. Here we show that the microscopic process of oxygen reduction repairs Cu deficiencies in the as-grown materials and creates oxygen vacancies in the stoichiometric CuO2 planes, effectively reducing disorder and providing itinerant carriers for superconductivity. The resolution of this long-standing materials issue suggests that the fundamental mechanism for superconductivity is the same for electron- and hole-doped copper oxides.