Role of Metal Lattice Expansion and Molecular pi-Conjugation for the Magnetic Hardening at Cu-Organics Interfaces

Martin-Olivera, Lorena, Shchukin, Dmitry G ORCID: 0000-0002-2936-804X and Teobaldi, Gilberto ORCID: 0000-0001-6068-6786 (2017) Role of Metal Lattice Expansion and Molecular pi-Conjugation for the Magnetic Hardening at Cu-Organics Interfaces. JOURNAL OF PHYSICAL CHEMISTRY C, 121 (42). pp. 23777-23787.

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Official URL: http://dx.doi.org/10.1021/acs.jpcc.7b08476

Abstract

Magnetic hardening and generation of room-temperature ferromagnetism at the interface between originally nonmagnetic transition metals and π-conjugated organics is understood to be promoted by interplay between interfacial charge transfer and relaxation-induced distortion of the metal lattice. The relative importance of the two contributions for magnetic hardening of the metal remains unquantified. Here, we disentangle their role via density functional theory simulation of several models of interfaces between Cu and polymers of different steric hindrance, π-conjugation, and electron-accepting properties: polyethylene, polyacetylene, polyethylene terephthalate, and polyurethane. In the absence of charge transfer, expansion and compression of the Cu face-centered cubic lattice is computed to lead to magnetic hardening and softening, respectively. Contrary to expectations based on the extent of π-conjugation on the organic and resulting charge transfer, the computed magnetic hardening is largest for Cu interfaced with polyethylene and smallest for the Cu-polyacetylene systems as a result of a differently favorable rehybridization leading to different enhancement of exchange interactions and density of states at the Fermi level. It thus transpires that neither the presence of molecular π-conjugation nor substantial charge transfer may be strictly needed for magnetic hardening of Cu-substrates, widening the range of organics of potential interest for enhancement of emergent magnetism at metal-organic interfaces.

Item Type:	Article
Depositing User:	Symplectic Admin
Date Deposited:	09 Oct 2017 08:07
Last Modified:	19 Jan 2023 06:53
DOI:	10.1021/acs.jpcc.7b08476
Open Access URL:	http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.7b084...
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3009834