Ballistic conductance of Ni nanowire with a magnetization reversal

TL;DR

This paper extends a quantum conductance calculation method to magnetic transition metals and investigates how a spin reversal in a Ni nanowire affects electron transmission, showing that it blocks d-electron conductance but allows s-electron transmission, resulting in a total conductance of 2G0.

Contribution

It generalizes the Choi and Ihm method for magnetic metals and applies it to analyze conductance in a Ni nanowire with a spin reversal, revealing spin-dependent conductance behavior.

Findings

Spin reversal blocks d-electron conductance at Fermi energy.

Two s-electrons are perfectly transmitted, yielding 2G0 total conductance.

Results align with recent experimental observations.

Abstract

The approach proposed by Choi and Ihm for calculating the ballistic conductance of open quantum systems is generalized to deal with magnetic transition metals. The method has been implemented with ultrasoft pseudopotentials and plane wave basis set in a DFT-LSDA ab-initio scheme. We present the quantum-mechanical conductance calculations for monatomic Ni nanowire with a single spin reversal. We find that a spin reversal blocks the conductance of $d$ electrons at the Fermi energy of the Ni nanowire. On the other hand, two $s$ electrons (one per each spin) are perfectly transmitted in the whole energy window giving $2G_0$ for the total conductance. The relevance of these results in connection with recent experimental data is discussed.