Complex band structure with ultrasoft pseudopotentials: fcc Ni and Ni nanowire

TL;DR

This paper extends a method for calculating complex band structures to magnetic transition metals using ultrasoft pseudopotentials, aiding future conductivity studies in open quantum systems.

Contribution

It generalizes an existing approach to magnetic transition metals within a DFT framework, enabling complex band structure calculations with ultrasoft pseudopotentials.

Findings

Complex band structure of bulk fcc Ni presented.

Complex band structure of monatomic Ni wire analyzed.

Implications for spin-dependent conductance in Ni nanocontacts discussed.

Abstract

We generalize to magnetic transition metals the approach proposed by Choi and Ihm for calculating the complex band structure of periodic systems, a key ingredient for future calculations of conductivity of an open quantum system within the Landauer-Buttiker theory. The method is implemented with ultrasoft pseudopotentials and plane wave basis set in a DFT-LSDA ab-initio scheme. As a first example, we present the complex band structure of bulk fcc Ni (which constitutes the tips of a Ni nanocontact) and monatomic Ni wire (the junction between two tips). Based on our results, we anticipate some features of the spin-dependent conductance in a Ni nanocontact.