Quantifying the Quantum Nature of High-spin YSR Excitations in Transverse Magnetic Field

Overview

Journal Sci Adv

Specialties Biology
Science

Date 2024 Oct 18

PMID 39423263

Authors

Niels P E van Mullekom

Benjamin Verlhac

Werner M J van Weerdenburg

Hermann Osterhage

Manuel Steinbrecher

Katharina J Franke

Alexander A Khajetoorians

Affiliations

Soon will be listed here.

Abstract

Excitations of individual and coupled spins on superconductors provide a platform to study quantum spin impurity models as well as a pathway toward realizing topological quantum computing. Here, we characterize, using ultralow temperature scanning tunneling microscopy/spectroscopy, the Yu-Shiba-Rusinov (YSR) states of individual manganese phthalocyanine molecules with high spin on an ultrathin lead film in variable transverse magnetic field. We observe two types of YSR excitations, depending on the adsorption geometry. Using a zero-bandwidth model, we detail the role of the magnetic anisotropy, spin-spin exchange, and Kondo exchange. We illustrate that one molecular type can be treated as an individual spin, whereas the other type is best described by a coupled spin system. Using the field dependence of the YSR excitations combined with modeling, we describe the quantum phase of each excitation type. These results provide an insight into the quantum nature of YSR excitations in magnetic field and a platform to study spin impurity models on superconductors in magnetic field.

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