Fig. 2: Non-universal current backbone in a multi-domain device.
From: Non-universal current flow near the metal-insulator transition in an oxide interface
a Current density images of a multi-domain region of sample C1, as a function of VG. Reducing VG, mono-domain regions became more inhomogeneous, while the boundaries remained conducting. As a result, more current flowed along the boundaries. The rightmost image shows complicated current paths in the mono-domain regions, interrupted by the boundaries. In such patterns the current-carrying backbone cannot have the universal fractal scaling dimension. The solid white lines indicate the edges of the pattern. The dashed white lines indicate positions of domains. Scale bar, 30 µm. b Logarithmically binned histogram of the current density of the leftmost and rightmost maps in a, transitioning from highly homogeneous conductivity on the metallic side, characterized by a narrow current distribution to disordered flow closer to the MIT, where the histograms spans three decades of current density. c Histograms of two mono-domain regions at VG = −66 V, showing variations in the current distributions between different mono-domains, particularly in the width of the distributions, and in the low-current behavior.
