2015/09/30 by Nino Hatter, Benjamin Heinrich, Benjamin W. Heinrich +5 · 142 citations
Physics and Astronomy · #Atomic physics #Condensed matter physics #Excited state #Ground state #Impurity #Magnetic impurity #Phase transition #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Quantum phase transition #Quantum phases #Quantum tunnelling #Quasiparticle #Scanning tunneling spectroscopy #Singlet state #Superconductivity #Topological Materials and Phenomena #cond-mat.mes-hall
paper · pdf · doi:10.1038/ncomms9988
published in Nature Communications 6(1), 8988 (Nature Portfolio) · 6 pages, 4 figures
arxiv created 2015/09/30 · openalex publication_date 2015/11/25 · arxiv updated 2015/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The exchange coupling between magnetic adsorbates and a superconducting substrate leads to Shiba states inside the superconducting energy gap and a Kondo resonance outside the gap. The exchange coupling strength determines whether the quantum many-body ground state is a Kondo singlet or a singlet of the paired superconducting quasiparticles. Here we use scanning tunnelling spectroscopy to identify the different quantum ground states of manganese phthalocyanine on Pb(111). We observe Shiba states, which are split into triplets by magnetocrystalline anisotropy. Their characteristic spectral weight yields an unambiguous proof of the nature of the quantum ground state. Our results provide experimental insights into the phase diagram of a magnetic impurity on a superconducting host and shine light on the effects induced by magnetic anisotropy on many-body interactions.