화학공학소재연구정보센터
Nature Nanotechnology, Vol.6, No.7, 408-412, 2011
Discovery of superconductivity in KTaO3 by electrostatic carrier doping
Superconductivity at interfaces has been investigated since the first demonstration of electric-field-tunable superconductivity in ultrathin films in 1960(1). So far, research on interface superconductivity has focused on materials that are known to be superconductors in bulk(1-9). Here, we show that electrostatic carrier doping can induce superconductivity in KTaO3, a material in which superconductivity has not been observed before(10,11). 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 x 10(14) to 3.7 x 10(14) cm(-2). The present result clearly shows that electrostatic carrier doping can lead to new states of matter at nanoscale interfaces.