Prospect for detecting magnetism of a single impurity atom using electron magnetic chiral dichroism

Devendra Negi,Lewys Jones,Peter A Van Aken,Ján Rusz,Paul M Zeiger,Juan-Carlos Idrobo

doi:10.1103/physrevb.100.104434

Abstract

Dopants, even single atoms, can influence the electrical and magnetic properties of materials. Here we demonstrate the opportunity for detecting the magnetic response of an embedded magnetic impurity in a nonmagnetic host material. We combine a depth sectioning approach with electron magnetic circular dichroism in scanning transmission electron microscopy to compute the depth-resolved magnetic inelastic-scattering cross section of single Co impurity buried in the host crystal of GaAs. Our calculations suggest that the magnetic dichroic signal intensity is sensitive to the depth and lateral position of the electron probe relative to the magnetic impurity. Additionally, a more precise dichroic signal localization can be achieved via choosing higher-collection-angle ($\ensuremath{\beta}$) apertures. Quantitative evaluation of the inelastic-scattering cross section and signal-to-noise ratio indicates that the magnetic signal from a single Co atom is on the verge of being detectable with today's state-of-the-art instrumentation.

Highlights

There is continuing interest in the preparation and characterisation of nanostructured metal films with feature sizes in the range 1–100 nm
Nanoparticle (NP) films of noble metals are of interest because they display a surface plasmon resonance (SPR) in the visible region, which can be used to enhance the sensitivity of fluorescence and Raman spectroscopies [2,3]
Alfonso et al (Ag and Cu on sapphire) [5,6], Dolbec et al (Pt on highly oriented pyrolytic graphite) [4], Donnelly et al (Ag and Au on glass, polymer and Si) [7,8] and Seal et al (Ag on Si) [9] have all investigated pulsed laser deposition (PLD) of metal NP films using nanosecond lasers in vacuum or low pressure background gases (

Summary

Introduction

There is continuing interest in the preparation and characterisation of nanostructured metal films with feature sizes in the range 1–100 nm. Alfonso et al (Ag and Cu on sapphire) [5,6], Dolbec et al (Pt on highly oriented pyrolytic graphite) [4], Donnelly et al (Ag and Au on glass, polymer and Si) [7,8] and Seal et al (Ag on Si) [9] have all investigated PLD of metal NP films using nanosecond (ns) lasers in vacuum or low pressure background gases (

Methods

Results

Conclusion