SKM 2023 – scientific programme
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O: Fachverband Oberflächenphysik
O 15: Spins on Surfaces at the Atomic Scale II
O 15.8: Talk
Monday, March 27, 2023, 16:45–17:00, REC C 213
A non equilibrium Green’s Function formalism applied to STM/ESR experiments — •Jose Reina-Galvez1, Nicolas Lorente2, and Christoph Wolf1 — 1Center for Quantum nanoscience, Seoul, South Korea — 2Centro de Fisica de Materiales, San Sebastian, Spain
The demonstration of reproducible single-atom and single-molecule electron spin resonance (ESR) in a STM junction opened new possibilities in the analysis of surface science at the atomic scale. Recent experiments have demonstrated quantum-coherent Rabi oscillations and even the implementation of a quantum logic operation: a CNOT gate.
Here, we want to focus on the theory we developed to reproduce some relevant results in the field. Our theoretical framework uses open quantum systems formalism in combination with non equilibrium Green’s Function technique. It consists of a quantum impurity connected to a polarized STM tip and an isolated surface, both considered as fermionic baths. The time dependent bias voltage used in the experiments is introduced in the hopping terms. These hoppings are driving the electron transitions from the baths to the quantum impurity which uses a modified Anderson impurity model with localized electronic states, a Coulomb repulsion term and a Zeeman term.
Our model is general, allowing to connect an arbitrary number of localized spins with the transport spin. We will demonstrate how driving the system on resonance modifies the population and the calculated true current through the many-body impurity which can be directly compared to the experiment.