Extended treatment of the surface in adatom simulations
Studies of Yu-Shiba-Rusinov band dispersion, field-emission resonances and coherent manipulation of atomic magnets
R. Broekhoven (TU Delft - QN/Otte Lab, TU Delft - QN/Akhmerov Group, TU Delft - QRD/Wimmer Group)
S. Otte – Promotor (TU Delft - QN/Otte Lab)
AR Akhmerov – Promotor (TU Delft - QN/Akhmerov Group)
M.T. Wimmer – Promotor (TU Delft - QN/Wimmer Group, TU Delft - QRD/Wimmer Group)
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Abstract
With a scanning tunneling microscope (STM), it is possible to study single atoms, the building blocks of all materials.
For STM measurements, these atoms, though, must in general always reside on a conducting surface, which affects them.
This thesis concerns the influence of a metal surface on measurements of three specific atomic systems.
The first system is chains of classical spins on a superconductor giving rise to Yu-Shiba-Rusinov in-gap band dispersion. We present a short junction surface scattering theory to evaluate the effective Hamiltonian of this dispersion, requiring only the unperturbed chain Hamiltonian and the Fermi self-energy of the surface.
The second system is field-emission resonances, which behave like artificial atoms when confined by chlorine vacancies on copper nitride and the STM tip. We use density function theory (DFT) to get increased insight into their lifetimes.
The final system is titanium atomic magnets, which can be coherently driven by electron spin resonance (ESR). We model these systems using open system dynamics to find what coherent operations are possible given the quantum coherence. Specific operations studied are a coherent flip-flop interaction between an electron and a nuclear spin, a proposal to create and detect entanglement, and, in the outlook, coherent spin evolution in spin chains.