Publications by authors named "P Willke"

Article Synopsis
  • Control of individual atomic spins is essential for advancements in spintronics, quantum sensing, and quantum information processing, with scanning tunneling microscopy (STM) being a effective tool for manipulation.
  • The research presents a new method for self-assembling magnetic organometallic complexes using iron atoms and specific molecules (Cu(dbm) and FePc) on a silver substrate, effectively forming complexes that mimic metallocenes.
  • Magnetic properties of these complexes show a notable Kondo effect, which is explained through density functional theory calculations indicating that the interaction between Fe 3d-orbitals and benzene π-orbitals enhances Kondo screening, offering insights for designing hybrid organometallic systems.
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The nuclear spin, being much more isolated from the environment than its electronic counterpart, presents opportunities for quantum experiments with prolonged coherence times. Electron spin resonance (ESR) combined with scanning tunnelling microscopy (STM) provides a bottom-up platform to study the fundamental properties of nuclear spins of single atoms on a surface. However, access to the time evolution of nuclear spins remained a challenge.

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Historically, electron spin resonance (ESR) has provided excellent insight into the electronic, magnetic, and chemical structure of samples hosting spin centers. In particular, the hyperfine interaction between the electron and the nuclear spins yields valuable structural information about these centers. In recent years, the combination of ESR and scanning tunneling microscopy (ESR-STM) has allowed to acquire such information about individual spin centers of magnetic atoms bound atop a surface, while additionally providing spatial information about the binding site.

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We study the properties of the Dirac states in SiC-graphene and its hole-doped compositions employing angle-resolved photoemission spectroscopy and density functional theory. The symmetry-selective measurements for the Dirac bands reveal their linearly dispersive behavior across the Dirac point which was termed as the anomalous region in earlier studies. No gap is observed even after boron substitution that reduced the carrier concentration significantly from 3.

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Control of single electron spins constitutes one of the most promising platforms for spintronics, quantum sensing, and quantum information processing. Utilizing single molecular magnets as their hosts establishes an interesting framework since their molecular structure is highly flexible and chemistry-based large-scale synthesis directly provides a way toward scalability. Here, we demonstrate coherent spin manipulation of single molecules on a surface, which we control individually using a scanning tunneling microscope in combination with electron spin resonance.

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