Fig. 4: Gate voltage-dependent Hall carrier density.
From: Stoichiometric control of electron mobility and 2D superconductivity at LaAlO3-SrTiO3 interfaces
The Hall resistance as a function out-of-plane magnetic field, RH(B⊥), for LAO/STO samples S4, S3, S2, and S1 with rLa/Al = 0.91 (a, e), 0.90 (b, f), 0.88 (c, g), and 0.84 (d, h) respectively. This is within the low gate voltage (VG) region of the phase diagram with linear dependence in RH(B⊥) (a–d), and at 50V where RH(B⊥) display nonlinear dependence (e–h). The black-dashed line indicates a linear fit of RH(B⊥). The black solid line is a fit of the two-band model (eq 1 presented in methods). i-l The evolution of carrier density as a function of VG extracted from the linear fit of RH(B⊥) for B⊥ < 0.5T (open circle) and B⊥ > 4T (solid circle). The shaded area indicates the region of VG where RH(B⊥) is nonlinear i.e. two bands regime. In the shaded region, n(B⊥ < 0.5T) vs. VG curve is not representing the true value of carrier density due to nonlinear RH(B⊥), whereas, n(B⊥ > 4T) is nearly equal to total carrier density \({n}_{T}={n}_{{d}_{xy}}+{n}_{{d}_{xz/yz}}\). Two arrows are the selection of gate voltage for which RH(B⊥) curves are shown. All measurements were performed at T = 2K.
