Cancellation of probe effects in measurements of spin polarized momentum density by electron positron annihilation

TL;DR

This paper demonstrates that electron-positron annihilation measurements can effectively reveal the spin-polarized momentum density and Fermi surface in ferromagnetic metals, overcoming previous interpretation challenges.

Contribution

It introduces a method to cancel probe effects in measurements, enabling detailed detection of spin-polarized electronic structures in ferromagnetic materials.

Findings

Effective cancellation of electron-positron matrix elements in ferromagnetic metals.

Successful calculation of momentum spin density and Fermi surface of CrO2.

Enhanced interpretability of electron-positron annihilation data for spintronics materials.

Abstract

Measurements of the two dimensional angular correlation of the electron-positron annihilation radiation have been done in the past to detect the momentum spin density and the Fermi surface. We point out that the momentum spin density and the Fermi Surface of ferromagnetic metals can be revealed within great detail owing to the large cancellation of the electron-positron matrix elements which in paramagnetic multiatomic systems plague the interpretation of the experiments. We prove our conjecture by calculating the momentum spin density and the Fermi surface of the half metal CrO2, who has received large attention due to its possible applications as spintronics material.