Thema der Dissertation:
Engineering Yu-Shiba-Rusinov states on 2H-NbSe2
Engineering Yu-Shiba-Rusinov states on 2H-NbSe2
Abstract: Unpaired adatom spins on superconductors induce Yu-Shiba-Rusinov (YSR) states inside the excitation gap. Using combined scanning tunneling microscopy and spectroscopy (STM/STS) methods, we can probe these states at the single-atom scale. Additionally, adatoms can be moved on surfaces with atomic precision by lateral manipulation using the STM tip. We use the STM tip to construct structures of Fe atoms on a 2H-NbSe2. If the YSR wave functions of two impurities overlap, they may hybridize forming a symmetric and an antisymmetric linear combination of the monomer wave functions similar to the linear combination of atomic orbitals when forming molecules. In large adatom structures YSR bands may form and, for specific parameter ranges, realize topological superconductivity. We use the symmetry of the substrate to construct chiral YSR molecules from only one atom species thereby emulating a molecule that cannot be realized in gas-phase chemistry. Additionally, we find a dimer in a partially screened ground state which is a promising starting point for a YSR chain that may host topological superconductivity. Upon extending the dimer to a chain we continue to observe the desired ground state but cannot find clear signs of topological superconductivity. We further demonstrate controlled manipulation of the incommensurate charge-density wave that coexists with superconductivity in 2H-NbSe2 at low temperatures by adatom manipulation and investigate Mn atoms as an alternative adsorbate.
Time & Location
Apr 09, 2025 | 03:30 PM
Hörsaal A (1.3.14)
(Fachbereich Physik, Arnimallee 14, 14195 Berlin)