Quantum Spin-Engineering in On-Surface Molecular Ferrimagnets

Wantong Huang; Máté Stark; Paul Greule; Kwan Ho Au-Yeung; Daria Sostina; José Reina Gálvez; Christoph Sürgers; Wolfgang Wernsdorfer; Christoph Wolf; Philip Willke

arXiv · 2410.18563

Quantum Spin-Engineering in On-Surface Molecular Ferrimagnets

Wantong Huang·Máté Stark·Paul Greule·Kwan Ho Au-Yeung·Daria Sostina·José Reina Gálvez·Christoph Sürgers·Wolfgang Wernsdorfer·Christoph Wolf·Philip Willke

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Abstract

The design and control of atomic-scale spin structures constitute major challenges for spin-based quantum technology platforms, including quantum dots, color centers, and molecular spins. Here, we showcase a strategy for designing the quantum properties of molecular spin qubits by combining tip-assisted on-surface assembly with electron spin resonance scanning tunneling microscopy (ESR-STM): We fabricate magnetic dimer complexes that consist of an iron phthalocyanine (FePc) molecule and an organometallic half-sandwich complex formed by the FePc ligand and an attached iron atom, Fe(C6H6). The total complex forms a mixed-spin (1/2,1) quantum ferrimagnet with a well-separated correlated ground state doublet, which we utilize for coherent control. As a result of the correlation, the quantum ferrimagnet shows an improved spin lifetime (>1.5 ${\mu}$s) as it is partially protected against inelastic electron scattering. Lastly, the ferrimagnet units also enable intermolecular coupling, that can be used to realize both ferromagnetic or antiferromagnetic structures. Thus, quantum ferrimagnets provide a versatile platform to improve coherent control in general and to study complex magnetic interactions.

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Wantong Huang, Máté Stark, Paul Greule, Kwan Ho Au-Yeung, Daria Sostina, José Reina Gálvez, Christoph Sürgers, Wolfgang Wernsdorfer, Christoph Wolf, Philip Willke. 2024-10-24. Quantum Spin-Engineering in On-Surface Molecular Ferrimagnets. https://arxiv.org/abs/2410.18563

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