Fig. 2: Superconducting phase diagram.
From: Stoichiometric control of electron mobility and 2D superconductivity at LaAlO3-SrTiO3 interfaces
a–d Resistance vs temperature curves measured between 0.4K - 0.03K at different gate voltage (VG) for samples with rLa/Al = 0.91, 0.90, 0.88, 0.84. e–h The corresponding color plot of normalized resistance as a function of temperature and VG. The color scale is the same for all panels. The dashed line in color plot represents VG for Lifshitz transition. i The modulation of critical temperature Tc as a function of total carrier density nT. Here the carrier density corresponding to the dashed line is extracted from polynomial extrapolation of the data in Fig. 4i–l. j The variation of maximum of superconducting \({{{{{{{{\rm{T}}}}}}}}}_{C}^{max}\) with La/Al ratio. k The dashed line, adapted from ref. 41, indicates insulating-to-metallic transition as a function of La/Al ratio. The data points represented by circles correspond to the values of the La/Al ratio in our samples, as estimated from XPS analysis. The phase diagram is divided into three different regions: superconducting (SC), normal metal (NM), and insulating (INS) based on the outcome of our result.
