Effects of spin-orbit coupling and many-body correlations in STM transport through copper phthalocyanine

TL;DR

This study investigates how spin-orbit interaction and many-body correlations influence the electronic spectrum and transport properties of copper phthalocyanine molecules, revealing signatures detectable via STM magnetoconductance measurements.

Contribution

The paper develops a minimal model Hamiltonian including spin-orbit effects to explain experimental observations in CuPc molecules, highlighting the impact on energy level splitting and magnetic anisotropy.

Findings

Spin-orbit interaction causes splitting of degenerate levels.

Magnetoconductance measurements can detect SOI-induced effects.

A low-energy spin Hamiltonian effectively describes the system.

Abstract

The interplay of exchange correlations and spin-orbit interaction (SOI) on the many-body spectrum of a copper phtalocyanine (CuPc) molecule and their signatures in transport are investigated. We first derive a minimal model Hamiltonian in a basis of frontier orbitals which is able to reproduce experimentally observed singlet-triplet splittings; in a second step SOI effects are included perturbatively. Major consequences of the SOI are the splitting of former degenerate levels and a magnetic anisotropy, which can be captured by an effective low-energy spin Hamiltonian. We show that STM-based magnetoconductance measurements can yield clear signatures of both these SOI induced effects.