Manipulation of the magnetic ground state of individual manganese phtalocyanines by coordination to CO molecules

TL;DR

This study demonstrates how coordinating CO molecules to manganese phthalocyanine molecules on a Bi(110) surface alters their magnetic state, switching between different Kondo regimes as observed by scanning tunneling spectroscopy.

Contribution

It reveals the controllable manipulation of the magnetic ground state of MnPc molecules through CO coordination, supported by experimental and first-principles calculations.

Findings

CO coordination reduces MnPc spin from S=1 to S=1/2

Transition from underscreened Kondo to mixed-valence state

Magnetic state can be reversibly switched by CO desorption

Abstract

We show that the magnetic state of individual manganese phthalocyanine (MnPc) molecules on a Bi(110) surface is modified when the Mn2+ center coordinates to CO molecules adsorbed on top. Using scanning tunneling spectroscopy we identified this change in magnetic properties from the broadening of a Kondo-related zero-bias anomaly when the CO-MnPc complex is formed. The original magnetic state can be recovered by selective desorption of individual CO molecules. First principle calculations show that the CO molecule reduces the spin of the adsorbed MnPc from S = 1 to S = 1=2 and strongly modifies the respective screening channels, driving a transition from an underscreened Kondo state to a state of mix-valence.