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@PHDTHESIS{Fahrendorf:139689,
      author       = {Fahrendorf, Sarah},
      title        = {{S}ingle {N}d{P}c$_{2}$ molecules on surfaces : adsorption,
                      interaction, and molecular magnetism},
      volume       = {57},
      school       = {Universität Köln},
      type         = {Dissertation},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2013-05663},
      isbn         = {978-3-89336-856-3},
      series       = {Schriften des Forschungszentrums Jülich. Reihe
                      Schlüsseltechnologien / Key Technologies},
      pages        = {100 S.},
      year         = {2013},
      note         = {Universität Köln, Diss., 2012},
      abstract     = {Single molecule magnets (SMMs) play an important role in
                      the field of molecular spintronics.They have huge potential
                      for application in molecular-spin-transistors,
                      molecular-spinvalves,and molecular quantum computing. SMMs
                      are characterized by high spin groundstates with zero-field
                      splitting leading to high relaxation barriers and long
                      relaxation times.A relevant class of molecules are the
                      lanthanide double-decker phthalocyanines (LaPc$_{2}$)with
                      only one metal atom sandwiched between two organic
                      phthalocyanine (Pc) ligands. For envisaged spintronic
                      applications it is important to understand the interaction
                      between the molecules and the substrate and its influence on
                      the electronic and magnetic properties. The subject of this
                      thesis is the investigation of the adsorbed neodymium
                      double-decker phthalocyanine (NdPc$_{2}$) by means of low
                      temperature scanning tunneling microscopy and spectroscopy
                      (STM and STS). The molecules are deposited by sublimation
                      onto different substrates. It is observed that a large
                      fraction of the double-decker molecules decomposes during
                      deposition. The decomposition probability strongly depends
                      on the chosen substrate. Therefore it is concluded that the
                      substrate modifies the electronic structure of the molecule
                      leading to a stabilization or destabilization of the
                      molecular entity. Charge transfer from the surface tothe
                      molecule is identified as a potential stabilizing mechanism.
                      The electronic and magnetic properties are investigated in
                      detail for adsorbed NdPc$_{2}$ molecules on Cu(100). The
                      results of the experimental study are compared to state-of
                      the-art density functional theory calculations performed by
                      our colleagues from the Peter Grünberg Institute (PGI-1) at
                      the Forschungszentrum Jülich. Interestingly, the lower Pc
                      ring of the molecule hybridizes intensely with the substrate
                      leading to strong chemisorption of the molecule, while the
                      upper Pc ring keeps its molecular type electronic states,
                      which can be energetically shifted by an external electric
                      field. Importantly, it is possible to get direct access to
                      the spin-polarized 4$\textit{f}$-states of the central Nd
                      ion by means of STM and STS. This important and unique
                      characteristic absent for late lanthanide double-decker
                      phthalocyanine molecules opens the door for direct reading
                      and writing of the molecular spin-state by purely electrical
                      means. In view of the intended investigations of the
                      magnetic properties of the NdPc$_{2}$ molecule coupled to
                      ferromagnetic surfaces, spin-polarized STM investigations of
                      the second atomic layer of Fe on W(110) are performed. Here,
                      bulk Cr-tips are used, which were ex-situ electrochemically
                      etched from a Cr rod. Further in-situ treatment is shown to
                      have no essential influence on the magnetic properties of
                      the tips. The reproducible and reliable preparation of the
                      ferromagnetic substrate and the Cr-tips is the basis for
                      further investigations of the NdPc$_{2}$ molecule adsorbed
                      on the second atomic layer of Fe on W(110). Preliminary STM
                      and STS results give strong evidence, that the direct access
                      to the spin-polarized 4$\textit{f}$-states is also feasible
                      after adsorption of the double-decker molecule on a
                      ferromagnetic substrate.},
      keywords     = {Dissertation (GND)},
      cin          = {PGI-6},
      ddc          = {500},
      cid          = {I:(DE-Juel1)PGI-6-20110106},
      pnm          = {422 - Spin-based and quantum information (POF2-422)},
      pid          = {G:(DE-HGF)POF2-422},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      url          = {https://juser.fz-juelich.de/record/139689},
}