Anomalous channel-width effect in devices of a−LaAlO3/KTaO3 superconducting two-dimensional electron gases

Abstract

The recent discovery of two-dimensional electron gas (2DEG) at KTaO3-based interfacial systems has attracted considerable interest, offering great potentials for engineering novel electronic devices. Previously, influences of fabrication conditions on the 2DEG quality have been extensively studied in the thin films. However, little is known about possible influences of the device fabrication process to the 2DEG property. In this work, we have fabricated Hall bar devices with different channel widths, using the superconducting 2DEG at the amorphous-LaAlO3/KTaO3 (111) heterointerface as a prototypical system. We found that the device properties are collaboratively tuned by the channel width and the oxygen growth pressure. In particular, when the sample is grown under an intermediate oxygen pressure, an anomalous channel-width effect is observed that narrowing the channel would effectively increase the carrier density, leading to enhanced superconducting onset temperature and spin-orbit coupling. Consequently, the 2DEG properties become almost continuously tunable by adding the channel width as a new tuning parameter. Our present work contributes to exploration of explicit fabrication control of the superconducting 2DEG for novel electronic applications.

Source-reported materials — not catalogue approval

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