Fundamental Oscillation Periods of the Interlayer Exchange Coupling beyond the RKKY Approximation

TL;DR

This paper introduces a general method to determine oscillation periods of interlayer exchange coupling, revealing additional non-RKKY periods linked to the spacer Fermi surface, with implications for FCC(110) structures.

Contribution

It presents a novel approach to identify oscillation periods beyond RKKY predictions and clarifies their relation to the Fermi surface, including conditions for non-RKKY oscillations.

Findings

Existence of non-RKKY oscillation periods confirmed in FCC(110) structures.

Non-RKKY periods do not directly correspond to the Fermi surface.

A general method for calculating oscillation periods is developed.

Abstract

A general method for obtaining the oscillation periods of the interlayer exchange coupling is presented. It is shown that it is possible for the coupling to oscillate with additional periods beyond the ones predicted by the RKKY theory. The relation between the oscillation periods and the spacer Fermi surface is clarified, showing that non-RKKY periods do not bear a direct correspondence with the Fermi surface. The interesting case of a FCC(110) structure is investigated, unmistakably proving the existence and relevance of non-RKKY oscillations. The general conditions for the occurrence of non-RKKY oscillations are also presented.