A hybrid optoelectronic Mott insulator

TL;DR

This paper introduces a hybrid optoelectronic approach using a photoconductor/strongly-correlated heterostructure to control the Mott metal-insulator transition with light, enabling tunable functionalities in correlated materials.

Contribution

It demonstrates a novel method to externally control the Mott transition using optical stimuli through engineered heterostructures, combining photoconductors with correlated oxides.

Findings

Large photoinduced resistivity changes observed.

Significant shifts in transition temperatures achieved.

Potential for extending to other controllable correlated systems.

Abstract

The coupling of electronic degrees of freedom in materials to create hybridized functionalities is a holy grail of modern condensed matter physics that may produce novel mechanisms of control. Correlated electron systems often exhibit coupled degrees of freedom with a high degree of tunability which sometimes lead to hybridized functionalities based on external stimuli. However, the mechanisms of tunability and the sensitivity to external stimuli are determined by intrinsic material properties which are not always controllable. A Mott metal-insulator transition, which is technologically attractive due to the large changes in resistance, can be tuned by doping, strain, electric fields, and orbital occupancy but cannot be, in and of itself, controlled externally with light. Here we present a new approach to produce hybridized functionalities using a properly engineered photoconductor/strongly-correlated hybrid heterostructure, showing control of the Metal-to-Insulator transition (MIT) using optical means. This approach combines a photoconductor, which does not exhibit an MIT, with a strongly correlated oxide, which is not photoconducting. Due to the close proximity between the two materials, the heterostructure exhibits large volatile and nonvolatile, photoinduced resistivity changes and substantial photoinduced shifts in the MIT transition temperatures. This approach can potentially be extended to other judiciously chosen combinations of strongly correlated materials with systems which exhibit optically, electrically or magnetically controllable behavior.