Fig. 3: Superconducting gap and mutual inductance measurements on FeSe/LFO/STO.
From: High temperature superconductivity at FeSe/LaFeO3 interface
a, d Surface morphology of the nominal 1uc FeSe/LFO/STO (a, sample bias = 4 V, tunneling current = 30 pA), and 1.5uc FeSe/LFO/STO sample (d sample bias = 2 V, tunneling current = 30 pA) measured by STM. Partial coverage of FeSe on one LFO terrace is illustrated as shaded area in panel a. b Symmetrized photoemission spectrum with respect to EF of the 1uc FeSe/LFO/STO across M measured with 1/8 I0 at 6 K. c Symmetrized EDC at the k1’s of 1uc FeSe/LFO/STO and the fitting to a superconducting spectral function based on the simplified Bardeen-Cooper-Schrieffer(BCS) self-energy19,60,61,62. e, f Symmetrized photoemission spectrum with respect to EF of the 1.5uc FeSe/LFO/STO across M measured at 31 and 56 K, respectively. g, h Temperature dependence of the symmetrized EDC at the k1', and the determined superconducting gap of 1.5uc FeSe/LFO/STO, respectively. The error bars of gap are from the s.d. of the fitting process and the measurement uncertainty. i Temperature dependence of the out-of-phase voltage Vout in the pickup coil measured by the ex-situ mutual inductance experiments on the a-Se capped 1.5uc FeSe/LFO/STO and a comparative sample of Se capped LFO/STO with the same heat treatment. j Diamagnetic signal of FeSe in varied magnetic field. Vout(FeSe) is obtained by the subtraction of Vout(Se/1.5uc FeSe/LFO/STO) by Vout(Se/LFO/STO) in i. k Comparison between Vout(Se/1.5uc FeSe/LFO/STO) in this work and Vout(Se/2uc FeSe/2uc (Fe0.96Co0.04)Se/1uc FeSe/STO) in Zhang et al.7 normalized by the corresponding 105K data.
