Nanoscale Control of the Metal-Insulator Transition at LaAlO<sub>3</sub>/KTaO<sub>3</sub> Interfaces.

Yu, Muqing; Liu, Changjiang; Yang, Dengyu; Yan, Xi; Du, Qianheng; Fong, Dillon D; Bhattacharya, Anand; Irvin, Patrick et al. · Nano Lett · 2022

basic_science · Level V

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Abstract

Recent reports of superconductivity at KTaO<sub>3</sub> (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 SrTiO<sub>3</sub> (STO)-based heterostructures. Here, we report the reconfigurable creation of conducting structures at intrinsically insulating LaAlO<sub>3</sub>/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) ultralow-voltage electron-beam lithography. At low temperatures, KTO(110)-based devices show superconductivity that is tunable by an applied back gate. A one-dimensional nanowire device shows single-electron-transistor (SET) behavior. A KTO(111)-based device is metallic but does not become superconducting. 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.