Layer Resolved Magnetotransport Properties in Antiferromagnetic/Paramagnetic Superlattices

TL;DR

This study explores layer-specific magnetotransport in antiferromagnetic/paramagnetic superlattices using a Hubbard model, revealing induced magnetic moments, antiferromagnetic ordering, and metal-insulator transitions influenced by layer interactions and thickness.

Contribution

It introduces a detailed layer-resolved analysis of magnetotransport properties in superlattices with correlated and uncorrelated layers using Monte Carlo simulations.

Findings

Induced magnetic moments appear in uncorrelated layers at low temperatures.

Antiferromagnetic order mediates between correlated layers via uncorrelated layers.

Long-range antiferromagnetic order diminishes with increasing uncorrelated layer thickness.

Abstract

We investigate the layer resolved magnetotransport properties of the antiferromagnetic/paramagnetic superlattices based on one band half-filled Hubbard model in three dimensions. In our set up the correlated layers (with on-site repulsion strength $U \ne$ 0) are intercalated between the uncorrelated (U = 0) layers. Our calculations based on the semi-classical Monte-Carlo technique show that the magnetic moments are induced in the uncorrelated layers at low temperatures due to kinetic hopping of the carriers across the interface. The average induced magnetic moment in the uncorrelated layer varies nonmonotonically with the $U$ values of the correlated layer. Interestingly, the induced magnetic moments are antiferromagnetically arranged in uncorrelated layers and mediates the antiferromagnetic ordering between correlated layers. As a result the whole SL system turns out to be antiferromagnetic insulating at low temperatures. For $U \sim$ bandwidth the local moments in the correlated planes increases as a function of the distance from the interface. Expectedly our in-plane resistivity calculations show that the metal insulator transition temperature of the central plane is larger than the edge planes in the correlated layers. On the other hand, although the induced moments in uncorrelated planes decreases considerably as move from edge planes to center planes the metal insulator transition temperature remains more or less same for all planes. The induced moments in uncorrelated layers gradually dissipates with increasing the thickness of uncorrelated layer and as a result the long range antiferromagnetic ordering vanishes in the superlattices similar to the experiments.