Spin-resolved Fermi surface of the localized ferromagnetic Heusler compound Cu$_2$MnAl measured with spin-polarized positron annihilation

TL;DR

This study uses spin-polarized positron annihilation to map the bulk electronic structure of Cu$_2$MnAl, revealing detailed Fermi surface features and magnetic properties with high accuracy.

Contribution

A new algorithm for reconstructing 3D electron densities from projections was developed, enabling precise comparison between experimental data and electronic structure calculations.

Findings

Excellent agreement between measurements and calculations.

Identified contributions of Fermi surface sheets to magnetization.

Measured total spin magnetic moment of 3.6 ± 0.5 μ_B per formula unit.

Abstract

We determined the bulk electronic structure in the prototypical Heusler compound Cu$_2$MnAl by measuring the Angular Correlation of Annihilation Radiation (2D-ACAR) using spin-polarized positrons. To this end, a new algorithm for reconstructing 3D densities from projections is introduced that allows us to corroborate the excellent agreement between our electronic structure calculations and the experimental data. The contribution of each individual Fermi surface sheet to the magnetization was identified, and summed to a total spin magnetic moment of $3.6\,\pm\,0.5\,\mu_B/\mathrm{f.u.}$.