Room-Temperature On-Spin-Switching and Tuning in a Porphyrin-Based Multifunctional Interface.

Henning Maximilian Sturmeit,Giovanni Comelli,Andreas Windischbacher,Chantal Hohner,Alessandro Sala,Matteo Jugovac,Jörg Libuda,Peter Puschnig,Giovanni Zamborlini,Alberto Verdini,Mirko Cinchetti,Albano Cossaro,Miroslav Kettner,Luca Floreano,Vitaliy Feyer,Cristina Africh,Claus M Schneider ,Matuš Stredansky ,Cínthia Piamonteze

doi:10.1002/smll.202104779

Abstract

Molecular interfaces formed between metals and molecular compounds offer a great potential as building blocks for future opto-electronics and spintronics devices. Here, a combined theoretical and experimental spectro-microscopy approach is used to show that the charge transfer occurring at the interface between nickel tetraphenyl porphyrins and copper changes both spin and oxidation states of the Ni ion from [Ni(II), S=0] to [Ni(I), S=1/2]. The chemically active Ni(I), even in a buried multilayer system, can be functionalized with nitrogen dioxide, allowing a selective tuning of the electronic properties of the Ni center that is switched to a [Ni(II), S = 1] state. While Ni acts as a reversible spin switch, it is found that the electronic structure of the macrocycle backbone, where the frontier orbitals are mainly localized, remains unaffected. These findings pave the way for using the present porphyrin-based system as a platform for the realization of multifunctional devices where the magnetism and the optical/transport properties can be controlled simultaneously by independent stimuli.

Highlights

In the last two decades, considerable efforts have been made to stabilize and control the spin and oxidation states in metal ions at the nanoscale in order to design devices with novel functionalities and improved performance
Www.small-journal.com is fully decoupled from the substrate underneath, and the +2 state of the Ni ion (Ni(II)) is preserved. This can be achieved by depositing the nickel tetraphenyl porphyrins (NiTPP) on a (√2 × 2√2)R45°-oxygen-reconstructed copper(100) surface (for simplicity referred to as O–Cu(100) in the following), where the covalent nature of the Cu–O interaction yields a strong localization of the surface electrons, inhibiting the charge transfer from the substrate to the molecular film.[26,27]
The central Ni ion carries the spin moment that depends on its oxidation state and its chemical coordination to the surroundings

Summary

Introduction

In the last two decades, considerable efforts have been made to stabilize and control the spin and oxidation states in metal ions at the nanoscale in order to design devices with novel functionalities and improved performance. This offers prospects for enhancing the reactivity of single-atom catalysts,[1] developing new strategies for efficient gas separation in metal–organic frameworks,[2] building single-atom magnets capable of storing information,[3] as well as realizing spin-based logic operations.[4]. One way to stabilize metal ions and to prevent their local magnetic moment from decreasing or being quenched by the.

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Conclusion