Extreme Reconfigurable Nanoelectronics at the CaZrO₃/SrTiO₃ Interface

Abstract

Complex oxide heterostructures have fascinating emergent properties that originate from the properties of the bulk constituents as well as from dimensional confinement. The conductive behavior of the polar/nonpolar LaAlO /SrTiO interface can be reversibly switched using conductive atomic force microscopy (c-AFM) lithography, enabling a wide range of devices and physics to be explored. Here, extreme nanoscale control over the CaZrO /SrTiO (CZO/STO) interface, which is formed from two materials that are both nonpolar, is reported. Nanowires with measured widths as narrow as 1.2 nm are realized at the CZO/STO interface at room temperature by c-AFM lithography. These ultrathin nanostructures have spatial dimensions at room temperature that are comparable to single-walled carbon nanotubes, and hold great promise for alternative oxide-based nanoelectronics, as well as offer new opportunities to investigate the electronic structure of the complex oxide interfaces. The cryogenic properties of devices constructed from quasi-1D channels, tunnel barriers, and planar gates exhibit gate-tunable superconductivity, quantum oscillations, electron pairing outside of the superconducting regime, and quasi-ballistic transport. This newly demonstrated ability to control the metal-insulator transition at nonpolar oxide interface greatly expands the class of materials whose behavior can be patterned and reconfigured at extreme nanoscale dimensions.

Epitaxial Oxides on Semiconductors: From Fundamentals to New Devices

“…Another attractive feature of oxide 2DEGs stems from the ability to “write” nanoscale conductive regions using a scanning probe tip, enabling so‐called sketched devices to be created . Such sketched devices open routes to study fundamental phenomena, or create nano‐scale devices for logic and sensing …”

Phase Instability amid Dimensional Crossover in Artificial Oxide Crystal

“…In general, the electronic density profile at the interface is broader than the chemical interface due to the prevailing charge transfer at the isostructural perovskite oxide heterointerfaces [22]. While polar discontinuity is a prominent example of the electronic reconstruction of the interface between a polar and a non-polar material [23], even some non-polar materials can form an interface with a substantial charge transfer manifesting the strong covalent or ionic bonding in the oxides [24]. Recently, Zhong and Hansmann proposed a band alignment scheme to quantitatively estimate the charge transfer at the complex oxide interfaces [25].…”

Diluted Oxide Interfaces with Tunable Ground States

“…Subsequent investigations reveal that the Lifshitz transition does not occur at a universal carrier density, but depends crucially on the electrostatic boundary conditions among other parameters . Notably, electric‐field‐induced metal‐insulator phase transitions have so far been largely limited to the critical film thickness before the conduction emerges . Additionally, most back gating experiments show that the electron mobility is lowered with the decrease of carrier density, although an opposite tendency, i.e., the electron mobility is increased upon decrease of carrier density, was recently observed in top gating configurations .…”