Ruderman-Kittel-Kasuya-Yosida spin density oscillations: impact of the finite radius of the exchange interaction

TL;DR

This paper investigates how a finite interaction radius affects the RKKY spin density oscillations in a one-dimensional electron gas, revealing significant deviations from the traditional zero-radius model at large electron numbers.

Contribution

It introduces the impact of finite interaction radius on RKKY oscillations, highlighting essential differences from the zero-radius approximation in a 1D ring model.

Findings

Finite interaction radius significantly alters spin density oscillations.

Large electron numbers amplify the effects of finite interaction radius.

Traditional zero-radius models may overlook critical oscillation features.

Abstract

A non-interacting electron gas on a one-dimensional ring is considered at finite temperatures. The localized spin is embedded at some point on the ring and it is assumed that the interaction between this spin and the electrons is the exchange interaction being the basis of the Ruderman-Kittel-Kasuya-Yosida indirect exchange effect. When the number of electrons is large enough, it turns out that any small but finite interaction radius value can always produce an essential change of the spin density oscillations in comparison with the zero interaction radius traditionally used to model the Ruderman-Kittel-Kasuya-Yosida effect.