Modulation of Quantum Transport in Complex Oxide Heterostructures with Proton Implantation

TL;DR

This study shows that proton implantation can precisely tune quantum transport in SrTiO3-based heterostructures by balancing charge doping and disorder, enabling control over interfacial electronic states.

Contribution

It introduces proton implantation as a novel method to modulate interfacial quantum transport in complex oxide heterostructures, revealing a nonmonotonic behavior driven by competing effects.

Findings

Charge doping enhances carrier density and mobility at low fluences.

Higher fluences increase disorder, suppressing mobility and causing insulating behavior.

Quantum transport oscillations emerge at low temperatures with controlled proton implantation.

Abstract

The interfacial electronic properties of complex oxides are governed by a delicate balance between charge transfer, lattice distortions, and electronic correlations, posing a key challenge for controlled tunability in materials research. Here, we demonstrate that proton implantation serves as a precise tool for modulating interfacial transport in SrTiO3-based heterostructures. By introducing protons into the SrTiO3 substrate beneath an amorphous (La,Sr)(Al,Ta)O3 capping layer, we uncover a competition between disorder and charge doping induced by implantation. At low implantation fluences below 1x1015 protons/cm2 (1E15), charge doping dominates, leading to an increase in carrier density and mobility, analogous to electrostatic gating effect. This enables the emergence of quantum transport oscillations at low temperature. Conversely, at higher fluences (above 1E15), disorder scattering prevails, suppressing carrier mobility and inducing an insulating state. The nonmonotonic evolution of transport with implantation fluence underscores the critical interplay between electronic correlations and disorder, offering a new paradigm for the controlled engineering of interfacial quantum states in SrTiO3-based oxide heterostructures.