Nonlocal Differential Resistance in AlO$_x$/KTaO$_3$ Heterostructures

TL;DR

This paper reports on anomalous local and nonlocal differential resistance behaviors in AlO$_x$/KTaO$_3$ heterostructures, influenced by crystal orientation and gate voltage, including a large nonlocal resistance over hundreds of microns.

Contribution

It reveals the presence of significant nonlocal differential resistance in AlO$_x$/KTaO$_3$ heterostructures and discusses potential sources of this anomalous behavior.

Findings

Asymmetric local differential resistance with antisymmetric component

Large nonlocal differential resistance observed over hundreds of microns

Dependence of behavior on crystal orientation and gate voltage

Abstract

Local and nonlocal differential resistance measurements on Hall bars defined in AlO$_x$/KTaO$_3$ heterostructures show anomalous behavior that depends on the crystal orientation and the applied back gate voltage. The local differential resistance is asymmetric in the dc bias current, with an antisymmetric component that grows with decreasing gate voltage. More surprisingly, a large nonlocal differential resistance is observed that extends between measurement probes that are separated by 100s of microns. The potential source of this anomalous behavior is discussed.