Interfacial and thickness effects in La$_{2/3}$Sr$_{1/3}$MnO$_3$/YBa$_2$Cu$_3$O$_{7}$ superlattices

TL;DR

This study uses first-principles calculations to analyze how interfacial strain and layer thickness influence electronic and magnetic properties in La$_{2/3}$Sr$_{1/3}$MnO$_3$/YBa$_2$Cu$_3$O$_{7}$ superlattices, revealing induced magnetism and charge transfer effects.

Contribution

It provides a detailed first-principles analysis of strain, thickness, and interfacial effects in LSMO/YBCO superlattices, highlighting magnetic and electronic modifications.

Findings

Epitaxial strain reduces buckling of CuO$_2$ planes.

Electron transfer occurs from LSMO to YBCO.

Interfacial copper atoms exhibit induced ferromagnetic moments.

Abstract

Superlattices of correlated oxides have been used to explore interfacial effects and to achieve additional control over the physical properties of individual constituents. In this work, we present a first-principles perspective of the strain and thickness effects in La$_{2/3}$Sr$_{1/3}$MnO$_3$/YBa$_2$Cu$_3$O$_{7}$ (LSMO/YBCO) superlattices. Our findings indicate that the presence of epitaxial strain and LSMO leads to a reduction of buckling parameters of the interfacial CuO$_2$ planes, as well as the transfer of electrons from LSMO to YBCO. In addition, the change in Cu-3$d$ valence is slightly dependent on the LSMO layer thickness. More interestingly, the in-plane ferromagnetic ground state within the CuO$_2$ planes near the interface is induced due to the local moments centered at the copper atoms. These local moments are decoupled from the charge transfer and, according to our calculations, appear mainly due to the Mn $3d$-O $2p$-Cu $3d$ hybridization being restricted to the interfacial region. The induced net magnetic ordering in interfacial copper atoms may have implications in the control of the superconducting state in the LSMO/YBCO superlattices.