Gate tunability of the superconducting state at the EuO/KTaO3 (111) interface

The recent discovery of superconducting interfaces in the KTaO3 (111)-based heterostructures is intriguing, since a much higher superconducting critical temperature (T-C; similar to 2K) is achieved compared to that in the SrTiO3 heterostructures (similar to 300 mK). In this paper, we report the superconducting properties of the EuO/KTaO3 (111) interface as a function of the interface carrier density (n(s)). The maximum T-C is observed to be similar to 2 K at n(s) similar to 1 x 10(14) cm(-2). In addition we show that the critical current density and the upper critical magnetic field can be effectively tuned by the back gate voltage. Interestingly, the gate dependence of the upper critical magnetic field exhibits a trend opposite to that of T-C in the underdoped region, suggesting a relatively larger Cooper pairing potential.