Non-universal current flow near the metal-insulator transition in an oxide interface

TL;DR

This study investigates the metal-insulator transition at LaAlO3/SrTiO3 interfaces, revealing that structural and electronic coupling disrupt universal scaling laws and alter current flow patterns near the transition.

Contribution

It demonstrates how structural domain boundaries influence current flow and prevent universal behavior at the metal-insulator transition in oxide interfaces.

Findings

Structural domain boundaries modify current flow near transition.

Universal scaling laws are disrupted by structural-electronic coupling.

Current flow patterns deviate from expected fractal behavior.

Abstract

In systems near phase transitions, macroscopic properties often follow algebraic scaling laws, determined by the dimensionality and the underlying symmetries of the system. The emergence of such universal scaling implies that microscopic details are irrelevant. Here, we locally investigate the scaling properties of the metal-insulator transition at the LaAlO3/SrTiO3 interface. We show that, by changing the dimensionality and the symmetries of the electronic system, coupling between structural and electronic properties prevents the universal behavior near the transition. By imaging the current flow in the system, we reveal that structural domain boundaries modify the filamentary flow close to the transition point, preventing a fractal with the expected universal dimension from forming. Our results offer a generic platform to engineer electronic transitions on the nanoscale.