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[资源] 一新材料绝对零度附近显超导性

研究人员在5月在线出版的《自然—纳米技术》期刊上首次报道，一种新材料在整体不具备超导性的情况下其表面显示出超导性。

超导性是指当材料被冷却到一定温度之下，电流可以没有阻性地通过其中，100年前，科学家第一次发现超导现象。Masashi Kawasaki和同事将金属电极置放在一层钽酸钾单晶上，然后加入一滴导电液体，让这个设备成为双层电晶体管。他们发现，这个晶体管产生的高电场导致钽酸钾晶体表面在高于绝对零度 0.005度的情况下成为超导体。

英文摘要

Superconductivity at interfaces has been investigated since the first demonstration of electric-field-tunable superconductivity in ultrathin films in 19601. So far, research on interface superconductivity has focused on materials that are known to be superconductors in bulk1, 2, 3, 4, 5, 6, 7, 8, 9. Here, we show that electrostatic carrier doping can induce superconductivity in KTaO3, a material in which superconductivity has not been observed before10, 11. Taking advantage of the large capacitance of the self-organized electric double layer that forms at the interface between an ionic liquid and KTaO3 (ref. 12), we achieve a charge carrier density that is an order of magnitude larger than the density that can be achieved with conventional chemical doping. Superconductivity emerges in KTaO3 at 50 mK for two-dimensional carrier densities in the range 2.3 × 1014 to 3.7 × 1014 cm−2. The present result clearly shows that electrostatic carrier doping can lead to new states of matter at nanoscale interfaces.

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