Growth-induced electron mobility enhancement at the LaAlO$_3$/SrTiO$_3$ interface

TL;DR

This study investigates how growth temperature affects the electron mobility at the LaAlO₃/SrTiO₃ interface, revealing that lower growth temperatures enhance mobility and reduce carrier density, with implications for electronic device performance.

Contribution

It demonstrates that growth temperature critically influences electron mobility and carrier density at the LaAlO₃/SrTiO₃ interface, providing insights for optimizing interface properties.

Findings

Interfaces grown at 650°C show highest mobility (~10,000 cm²/Vs) and lowest carrier density.

Higher growth temperatures (800-900°C) result in lower mobility (~1,000 cm²/Vs) and higher carrier density.

Reducing carrier density via field effect decreases mobility and induces weak localization.

Abstract

We have studied the electronic properties of the 2D electron liquid present at the LaAlO$_3$/SrTiO$_3$ interface in series of samples prepared at different growth temperatures. We observe that interfaces fabricated at 650{\deg}C exhibit the highest low temperature mobility ($\approx 10000 \textrm{ cm}^2/\textrm{Vs}$) and the lowest sheet carrier density ($\approx 5\times 10^{12} \textrm{ cm}^{-2}$). These samples show metallic behavior and Shubnikov-de Haas oscillations in their magnetoresistance. Samples grown at higher temperatures (800-900{\deg}C) display carrier densities in the range of $\approx 2-5 \times 10^{13} \textrm{ cm}^{-2}$ and mobilities of $\approx 1000 \textrm{ cm}^2/\textrm{Vs}$ at 4K. Reducing their carrier density by field effect to $8\times 10^{12} \textrm{ cm}^{-2}$ lowers their mobilites to $\approx 50 \textrm{ cm}^2/\textrm{Vs}$ bringing the conductance to the weak-localization regime.