Modulation Doping of a Mott Quantum Well by a Proximate Polar Discontinuity

TL;DR

This paper demonstrates a method for tunable hole-doping in oxide heterostructures by using polar discontinuity to induce electronic reconstruction in LaAlO3/LaVO3/LaAlO3 quantum wells, revealing a crossover from atomic to electronic surface reconstruction.

Contribution

It introduces a novel approach to modulate hole injection in oxide quantum wells via proximity to a polar surface, enabling tunable doping.

Findings

Exponential resistance drop observed below 10-15 unit cells.

Decreasing positive Seebeck coefficient indicates hole injection.

Crossover from atomic to electronic reconstruction identified.

Abstract

We present evidence for hole injection into LaAlO3/LaVO3/LaAlO3 quantum wells near a polar surface of LaAlO3 (001). As the surface is brought in proximity to the LaVO3 layer, an exponential drop in resistance and a decreasing positive Seebeck coefficient is observed below a characteristic coupling length of 10-15 unit cells. We attribute this behavior to a crossover from an atomic reconstruction of the AlO2-terminated LaAlO3 surface to an electronic reconstruction of the vanadium valence. These results suggest a general approach to tunable hole-doping in oxide thin film heterostructures.