Flexoelectrical Generation of Quantum Electronic States in Oxide Cracks

Cracks in thin films have traditionally been considered as undesirable failures that disrupt the normal epitaxial structures in oxide films. In these crack systems, unusual electrical transport properties have emerged [1], which are related crucially to the local symmetry breaking via strain gradients at and near the cracks. Therefore, given a well-controlled crack structure, cracks can act as functional components in electronic systems. Here, we explore the quantum electronic conduction properties of oxide heterostructures incorporating strain-induced cracks. Polar textures with topological magnetic edge states emerge due to the strain gradient, and the textures can be controlled by an external electric field. These states can induce discrete conduction levels similar to the Coulomb staircase phenomenon. This study may unleash an exotic dimension of nanoelectronics research.

[1] Y. Yeo et al., Configurable Crack Wall Conduction in a Complex Oxide, Nano Letters 23, 398 (2023).