Showing papers by "Maurits W. Haverkort published in 2014"
TL;DR: Using circularly polarized light combined with spin- and angle-resolved photoemission spectroscopy, the value of the effective spin-orbit coupling is directly measured to be 130±30 meV, even larger than theoretically predicted and comparable to the energy splitting of the dxy and dxz,yz orbitals around the Fermi surface.
Abstract: Spin-orbit coupling has been conjectured to play a key role in the low-energy electronic structure of Sr2RuO4. By using circularly polarized light combined with spin- and angle-resolved photoemission spectroscopy, we directly measure the value of the effective spin-orbit coupling to be 130 � 30 meV. This is even larger than theoretically predicted and comparable to the energy splitting of the dxy and dxz;yz orbitals around the Fermi surface, resulting in a strongly momentum-dependent entanglement of spin and orbital character in the electronic wavefunction. As demonstrated by the spin expectation value h sk · s−ki calculated for a pair of electrons with zero total momentum, the classification of the Cooper pairs in terms of pure singlets or triplets fundamentally breaks down, necessitating a description of the unconventional superconducting state of Sr2RuO4 in terms of these newly found spin-orbital entangled eigenstates.
143 citations
TL;DR: In this article, the exact diagonalization technique is employed in an efficient way to solve the correlated impurity problem for a large bath within the dynamical mean field approach, which is used in this paper.
Abstract: The exact diagonalization technique is employed in an efficient way to solve the correlated impurity problem for a large bath within the dynamical mean-field approach.
134 citations
TL;DR: It follows that photoelectron spin-polarization control is generically achievable in systems with a layer-dependent, entangled spin-orbital texture.
Abstract: spin-polarization. We demonstrate the � 100% reversal of a single component of the measured spinpolarizationvector upon the rotation of light polarization, as well as full three-dimensional manipulation by varying experimental configuration and photon energy. While a material-specific density-functional theory analysis is needed for the quantitative description, a minimal yet fully generalized two-atomic-layer model qualitatively accounts for the spin response based on the interplay of optical selection rules, photoelectron interference, and topological surface-state complex structure. It follows that photoelectron spin-polarization control is generically achievable in systems with a layer-dependent, entangled spin-orbital texture.
82 citations
TL;DR: In this article, a dynamical mean-field theory was used to capture band excitations, resonances, edge singularities and excitons in core level x-ray absorption spectroscopy (XAS) and core level photo electron spectrography (cPES) on metals, correlated metals and Mott insulators.
Abstract: Using a recently developed impurity solver we exemplify how dynamical mean-field theory captures band excitations, resonances, edge singularities and excitons in core level x-ray absorption spectroscopy (XAS) and core level photo electron spectroscopy (cPES) on metals, correlated metals and Mott insulators. Comparing XAS at different values of the core-valence interaction shows how the quasiparticle peak in the absence of core-valence interactions evolves into a resonance of similar shape, but different origin. Whereas XAS is rather insensitive to the metal insulator transition, cPES can be used, due to nonlocal screening, to measure the amount of local charge fluctuation.
69 citations
TL;DR: A novel analysis scheme for resonant X-ray reflectivity maps is introduced to determine profiles, which is element specific and non-destructive, and which exhibits atomic-layer resolution and a probing depth of hundreds of nanometers.
Abstract: The electronic phase behavior and functionality of interfaces and surfaces in complex materials are strongly correlated to chemical composition profiles, stoichiometry and intermixing. Here a novel analysis scheme for resonant X-ray reflectivity maps is introduced to determine such profiles, which is element specific and non-destructive, and which exhibits atomic-layer resolution and a probing depth of hundreds of nanometers.
58 citations
TL;DR: In this paper, a dynamical mean field theory was used to capture band excitations, resonances, edge singularities and excitons in core level x-ray absorption (XAS) and core level photo electron spectroscopy (cPES) on metals, correlated metals and Mott insulators.
Abstract: Using a recently developed impurity solver we exemplify how dynamical mean field theory captures band excitations, resonances, edge singularities and excitons in core level x-ray absorption (XAS) and core level photo electron spectroscopy (cPES) on metals, correlated metals and Mott insulators. Comparing XAS at different values of the core-valence interaction shows how the quasiparticle peak in the absence of core-valence interactions evolves into a resonance of similar shape, but different origin. Whereas XAS is rather insensitive to the metal insulator transition, cPES can be used, due to nonlocal screening, to measure the amount of local charge fluctuation.
12 citations