Giant resistance change across the phase transition in spin crossover molecules

TL;DR

This paper demonstrates theoretically that spin crossover molecules exhibit a giant resistance change at the phase transition, with potential applications in molecular spintronic devices due to their large magnetoresistance effect.

Contribution

It provides a theoretical analysis showing a large resistance change in spin crossover molecules during phase transition, highlighting their suitability for molecular spintronic applications.

Findings

Resistance increases by up to four orders of magnitude at phase transition

Magnetoresistance effect exceeds 3,000%

Electronic gap change drives the resistance variation

Abstract

The electronic origin of a large resistance change in nanoscale junctions incorporating spin crossover molecules is demonstrated theoretically by using a combination of density functional theory and the non-equilibrium Green's functions method for quantum transport. At the spin crossover phase transition there is a drastic change in the electronic gap between the frontier molecular orbitals. As a consequence, when the molecule is incorporated in a two terminal device, the current increases by up to four orders of magnitude in response to the spin change. This is equivalent to a magnetoresistance effect in excess of 3,000 %. Since the typical phase transition critical temperature for spin crossover compounds can be extended to well above room temperature, spin crossover molecules appear as the ideal candidate for implementing spin devices at the molecular level.