Two-dimensional electron gas at the interface of the ferroelectric-antiferromagnetic heterostructure Ba_0.8Sr_0.2TiO_3/LaMnO_3

TL;DR

This study investigates the electrical resistivity and electronic properties of Ba_0.8Sr_0.2TiO_3/LaMnO_3 heterostructures, revealing a temperature-induced insulator-metal transition and the formation of a two-dimensional electron gas at the interface.

Contribution

It provides new insights into the interface electronic structure of ferroelectric-antiferromagnetic heterostructures, demonstrating the emergence of a 2D electron gas through combined experimental and ab-initio methods.

Findings

Resistivity decreases significantly in certain orientations.

Insulator-metal transition occurs below ~160 K.

Formation of a 2D electron gas at the interface.

Abstract

The temperature dependence of the electrical resistivity of the heterostructures consisting of single crystalline LaMnO$_3$ samples with different crystallographic orientations covered by the epitaxial ferroelectric Ba$_{0.8}$Sr$_{0.2}$TiO$_3$ film has been studied. Results obtained for the heterostructure have been compared with the electrical resistivity of the single crystalline LaMnO$_3$ without the film. It was found that for the samples with the films where the polarization axis is perpendicular to the crystal surface the electrical resistivity strongly decreases, and at the temperature below ~160 K undergoes the insulator-metal transition. Ab-initio calculations were also performed for the structural and electronic properties of the BaTiO$_3$/LaMnO$_3$ heterostructure. Transition to the 2D electron gas at the interface is shown.