Detection of the electrostatic spin crossover effect in magnetic molecules

TL;DR

This paper demonstrates that scanning tunneling microscopy can detect the electrostatic spin crossover effect in magnetic molecules by observing characteristic conductance drops and inelastic transition behaviors.

Contribution

It introduces a method to identify the electrostatic spin crossover effect using STM, highlighting its unique conductance signatures and behavior under magnetic fields.

Findings

Large conductance drop indicates spin crossover.

Inversion of ground and excited states occurs without symmetry change.

Conductance steps split identically in magnetic field.

Abstract

Scanning tunneling microscopy (STM) can be used to detect inelastic spin transitions in magnetic nano-structures comprising only a handful of atoms. Here we demonstrate that STM can uniquely identify the electrostatic spin crossover effect, whereby the exchange interaction between two magnetic centers in a magnetic molecule changes sign as a function of an external electric field. The fingerprint of such effect is a large drop in the differential conductance as the bias increases. Crucially in the case of a magnetic dimer the spin crossover transition inverts the order between the ground state and the first excited state, but does not change their symmetry. This means that at both sides of the conductance drop associated to the spin crossover transition there are two inelastic transition between the same states. The corresponding conductance steps split identically in a magnetic field and provide a unique way to identify the electrostatic spin crossover.