Quantum Interference of Surface-Induced Friedel Oscillations Enhanced by Fermi-Surface Nesting in Layered Manganites

TL;DR

This paper investigates surface-induced Friedel oscillations in layered manganites, revealing quantum interference effects that could enhance surface properties relevant for battery cathodes and catalysts.

Contribution

It introduces an orbital degenerate double-exchange model to analyze surface Mn ion imbalances and uncovers quantum interference phenomena in Friedel oscillations.

Findings

Surface Mn4+ ions are more abundant on the surface than in the bulk.

Quantum beat phenomena emerge due to Friedel oscillation interference.

Results suggest potential improvements for Li-ion battery cathodes.

Abstract

Imbalance of Mn3+ and Mn4+ ions between surface and bulk in layered manganites is investigated on the basis of an orbital degenerate double-exchange model with surfaces. For two types of t2g spin structures, the number of Mn4+ ions on the surface is found to be larger than that in the bulk, explained by the surface-induced Friedel oscillation. In particular, for the sheet-type antiferromagnetic state, quantum beat phenomenon appears due to the interference among Friedel oscillations and the number of Mn4+ ions tends to increase on the surface. The present results are believed to be useful to develop high-efficient cathodes in Li-ion batteries and catalysts.