Nanoscale control of the metal-insulator transition at LAO/KTO (110) and LAO/KTO (111) interfaces

TL;DR

This paper demonstrates nanoscale control of the metal-insulator transition at LAO/KTO interfaces, revealing superconductivity and single-electron transistor behavior, enabling advanced quantum device development.

Contribution

It introduces two nanoscale fabrication methods for LAO/KTO interfaces and explores their superconducting and electronic properties.

Findings

Superconductivity observed at KTO interfaces with tunability via back gate.

Nanoscale devices exhibit single-electron transistor behavior.

Reconfigurable fabrication methods enable new quantum device research.

Abstract

Recent reports of superconductivity at KTaO3 (KTO) (110) and (111) interfaces have sparked intense interest due to the relatively high critical temperature as well as other properties that distinguish this system from the more extensively studied SrTiO3 (STO)-based heterostructures. Here we report nanoscale control of the metal-to-insulator transition at the LaAlO3/KTO (110) and (111) interfaces. Devices are created using two distinct methods previously developed for STO-based heterostructures: (1) conductive atomic-force microscopy lithography and (2) ultra-low-voltage electron-beam lithography. At low temperatures, KTO-based devices show superconductivity that is tunable by an applied back gate. A nanowire device shows single-electron-transistor (SET) behavior. These reconfigurable methods of creating nanoscale devices in KTO-based heterostructures offer new avenues for investigating mechanisms of superconductivity as well as development of quantum devices that incorporate strong spin-orbit interactions, superconducting behavior, and nanoscale dimensions.