# Electrically addressing the spin of a magnetic porphyrin through covalently connected graphene electrodes

## TL;DR

This study demonstrates the electrical control of spin states in a magnetic porphyrin molecule connected via graphene nanoribbons, advancing molecular spintronics by enabling spin manipulation through covalent graphene electrodes.

## Contribution

First demonstration of electrically addressing spin states in a magnetic porphyrin using covalently connected graphene nanoribbon electrodes.

## Key findings

- Electrons tunneling excite the spin multiplet of the magnetic porphyrin.
- Detachment of spin-centers shifts spin-carrying orbitals, restoring original spin states.
- Presence of spin-polarized resonances in free-standing systems confirms electrical addressability.

## Abstract

We report on the fabrication and transport characterization of atomically-precise single molecule devices consisting of a magnetic porphyrin covalently wired by graphene nanoribbon electrodes. The tip of a scanning tunneling microscope was utilized to contact the end of a GNR-porphyrin-GNR hybrid system and create a molecular bridge between tip and sample for transport measurements. Electrons tunneling through the suspended molecular heterostructure excited the spin multiplet of the magnetic porphyrin. The detachment of certain spin-centers from the surface shifted their spin-carrying orbitals away from an on-surface mixed-valence configuration, recovering its original spin state. The existence of spin-polarized resonances in the free-standing systems and their electrical addressability is the fundamental step for utilization of carbon-based materials as functional molecular spintronics systems.