Related papers: Core Electron Spectroscopic Studies for 11-Fe-base…
We study the electron-energy loss spectra of strongly correlated electronic systems doped away from half-filling using dynamical mean-field theory ($d=\infty$). The formalism can be used to study the loss spectra in the optical (${\bf…
We study the core hole-electron correlation in coherently coupled molecules by energy dispersive near edge X-ray absorption fine-structure spectroscopy. In a transient phase, which exists during the transition between two bulk arrangements,…
We have investigated the electronic structures of recently discovered superconductor FeSe by soft-x-ray and hard-x-ray photoemission spectroscopy with high bulk sensitivity. The large Fe 3d spectral weight is located in the vicinity of the…
Widely employed Near-Edge X-Ray Absorption Fine Structure (NEXAFS) spectroscopy probes a system by excitation of core electrons to unoccupied states. A variety of different methodologies are available to simulate corresponding spectra from…
Using the "break-junction" technique we prepared and studied superconductor - constriction - superconductor nanocontacts in polycrystalline samples of Fe-based superconductors CeO$_{0.88}$F$_{0.12}$FeAs (Ce-1111; $T_C^{\rm bulk} = 41 \pm 1…
We study the electronic properties of the $\textrm{Fe}\textrm{Se}_{1-x}\textrm{Te}_x$ system ($x=0$, 0.25, 0.5, 0.75, and 1) from the perspective of X-ray spectroscopy and density functional theory (DFT). The analysis performed on the…
In this work we present an interpretation of experimental O K-edge x-ray absorption near edge structure (XANES) in perovskite-type WO3 and AWO3 compounds (A = H and Na) using three different first principles approaches: (i)…
A model of the non-concentric spherical core-shell quantum dot under the influence of an externally applied electric field was proposed. It was established that the energy spectrum of both the electron and the hole depends on the intensity…
X-ray absorption fine-structure (XAFS) measurements supported by {\em ab initio} computations within the density functional theory (DFT) are employed to systematically characterize Fe-doped as well as Fe and Si-co-doped films grown by…
{\it Ab initio} calculations of relativistic electron energy loss spectra (REELS) are carried out using a generalization of the real-space Green's function code FEFF8 which is applicable to general aperiodic materials. Our approach…
Finite temperature field theory is used to calculate the correction to the mass of the electron in plasma with finite temperature and arbitrary chemical potential, and the results are applied to the core regions of type II supernovae (SNe).…
The ionization edges encoded in the electron energy loss spectroscopy (EELS) spectra enable advanced material analysis including composition analyses and elemental quantifications. The development of the parallel EELS instrument and fast,…
We study Fermi edge singularities in photo-absorption spectra of generic mesoscopic systems such as quantum dots or nanoparticles. We predict deviations from macroscopic-metallic behavior and propose experimental setups for the observation…
After a review of temperature-dependent experimental x-ray absorption near-edge structure (XANES) and related theoretical developments, we present the Al K-edge XANES spectra of corundum and beryl for temperature ranging from 300K to 930K.…
We combine electron energy-loss spectroscopy (EELS) and density functional theory (DFT) calculations to study the dispersion and effective mass of excitons in the bulk of WSe$_2$. Our EELS data suggest substantial deviations from the…
We present Fe K$\beta$ X-ray emission (XES) and Fe K X-ray absorption spectra (XAS) of Iron(II)sulfide (FeS) and Iron(II)disulfide (FeS$_2$). While XES and XAS offer different discrimination capabilities for chemical speciation, depending…
A comprehensive ellipsometric study was performed on Fe$_{1-x}$Co$_{x}$Si single crystals in the spectral range from 0.01 eV to 6.2 eV. Direct and indirect band gaps of 73 meV and 10 meV, respectively, were observed in FeSi at 7 K. One of…
The temperature and pressure dependence of the partial density of phonon states of iron atoms in superconducting Fe1.01Se was studied by 57Fe nuclear inelastic scattering (NIS). The high energy resolution allows for a detailed observation…
Absorbing a focused, femtosecond X-ray pulse from a Free-Electron Laser (FEL) can lead to extreme electronic excitations in solids. This excitation drives changes of the electronic system over the course of the pulse duration and the…
We concentrate here on photon absorption as well as electron and positron scattering upon endohedrals that consist of a fullerenes shell and an inner atom A. The aim is to understand the effect of fullerene electron shell in formation of…