Simulation of inelastic spin flip excitations and Kondo effect in STM spectroscopy of magnetic molecules on metal substrates

Abstract

Single-ion magnetic anisotropy in molecular magnets leads to spin flip excitations that can be measured by inelastic scanning tunneling microscope (STM) spectroscopy. Here I present a semi ab initio scheme to compute the spectral features associated with inelastic spin flip excitations and Kondo effect of single molecular magnets. To this end density functional theory calculations of the molecule on the substrate are combined with more sophisticated many-body techniques for solving the Anderson impurity problem of the spin-carrying orbitals of the magnetic molecule coupled to the rest of the system, containing a phenomenological magnetic anisotropy term. For calculating the STM spectra an exact expression for the dI/dV in the ideal STM limit, when the coupling to the STM tip becomes negligibly small, is derived. In this limit the dI/dV is simply related to the spectral function of the molecule-substrate system. For the case of an Fe porphyrin molecule on the Au(111) substrate, the calculated STM spectra are in good agreement with recently measured STM spectra, showing the typical step features at finite bias associated with spin flip excitation of a spin-1 quantum magnet. For the case of Kondo effect in Mn porphyrin on Au(111), the agreement with the experimental spectra is not as good due to the neglect of quantum interference in the tunneling.

References in corpus (12)

• Calculations of Hubbard U from first-principles
• Double Counting in LDA+DMFT - The Example of NiO
• Properties of anisotropic magnetic impurities on surfaces
• Dynamical Mean-Field Theory for Molecular Electronics: Electronic Structure and Transport Properties
• Orbital-selective spin excitation of a magnetic porphyrin
• Many-particle effects in adsorbed magnetic atoms with easy-axis anisotropy: the case of Fe on CuN/Cu(100) surface
• Towards a full ab initio theory of strong electronic correlations in nanoscale devices
• Quantum transport simulation scheme including strong correlations and its application to organic radicals adsorbed on gold
• Shifting the Voltage Drop in Electron Transport through a Single Molecule
• Renormalization of myoglobin-ligand binding energetics by quantum many-body effects
• Many-body spectral functions from steady state density functional theory
• Renormalization of single-ion magnetic anisotropy in the absence of Kondo effect

Cited by in corpus (5)

• Observation of fractional edge excitations in nanographene spin chains
• Electrically addressing the spin of a magnetic porphyrin through covalently connected graphene electrodes
• Renormalization of spin excitations and Kondo effect in open shell nanographenes
• Dynamical Mean-Field Theory for spin-dependent electron transport in spin-valve devices
• Temperature evolution of the Kondo peak beyond Fermi liquid theory