Related papers: Core Electron Spectroscopic Studies for 11-Fe-base…
We report an in-plane optical spectroscopy study on the iron-selenide superconductor K$_{0.75}$Fe$_{1.75}$Se$_2$. The measurement revealed the development of a sharp reflectance edge below T$_c$ at frequency much smaller than the…
We calculate the x-ray absorption near edge structure (XANES) modulating the Ba 4d-photoabsorption cross section - the giant dipole resonance - centered around 110 eV photon energy for several models of spherical and non-spherical Ba@C_n…
We study the crystalline and electronic properties of the $\textrm{Fe}_{1-x}\textrm{Co}_x\textrm{Se}$ system ($x=0$, 0.25, 0.5, 0.75, and 1.0) using X-ray diffraction, X-ray spectroscopy and density functional theory. We show that the…
We have developed a spin-resolved resonant electron energy-loss spectroscopy (SR-rEELS) in the primary energy of 0.3--1.5 keV, which corresponds to the core excitations of $2p$-$3d$ absorption of transition metals and $3d$-$4f$ absorption…
In the iron-based superconductors, understanding the relation between superconductivity and electronic structure upon doping is crucial for exploring the pairing mechanism. Recently it was found that in iron selenide (FeSe), enhanced…
We present a hybrid approach for GW/Bethe-Salpeter Equation (BSE) calculations of core excitation spectra, including x-ray absorption (XAS), electron energy loss spectra (EELS), and non-resonant inelastic x-ray scattering (NRIXS). The…
Rapid proliferation of hyperspectral imaging in scanning probe microscopies creates unique opportunities to systematically capture and categorize higher dimensional datasets, toward new insights into electronic, mechanical and chemical…
Transition Edge Sensor (TES) spectrometers for hard X-ray beamline science will enable improved X-ray emission and absorption spectroscopy in the information-rich 2 to 20 keV energy range. We are building a TES-based instrument for the…
A quantum-mechanical model to calculate the electron energy-loss spectra (EELS) for the system of a closely located metallic nanoshell and a molecule has been developed. At the resonance between the molecular excitation and plasmon modes in…
We present detailed LDA'+DMFT investigation of doping dependence of correlation effects in novel K{1-x}Fe{2-y}Se2 superconductor. Calculations were performed at four different hole doping levels, starting from hypothetical stoichiometric…
Energy states below the bandgap of a semiconductor, such as trap states or charge transfer states in organic donor acceptor blends, can contribute to light absorption. Due to their low number density or ultrasmall absorption cross-section,…
We consider electron-phonon (\textit{e-ph}) energy loss rate in 3D and 2D multi-component electron systems in semiconductors. We allow general asymmetry in the \textit{e-ph} coupling constants (matrix elements), i.e., we allow that the…
Angle-resolved photoemission spectroscopy (ARPES) is used to study the scattering rates of charge carriers from the hole pockets near Gamma in the iron-based high-Tc hole doped superconductors KxBa1-xFe2As2 x=0.4 and KxEu1-xFe2As2 x=0.55$…
Following the discovery of the potentially very high temperature superconductivity in monolayer FeSe we investigate the doping effect of Se vacancies in these materials. We find that Se vacancies pull a vacancy centered orbital below the…
We employ Momentum-Resolved Electron Energy Loss Spectroscopy (M-EELS) on Bi2.1Sr1.9CaCu2O8+x to resolve the issue of the kink feature in the electron dispersion widely observed in the cuprates. To this end, we utilize the GW approximation…
We propose a setup enabling electron energy loss spectroscopy to determine the density of the electrons accumulated by an electro-positive dielectric in contact with a plasma. It is based on a two-layer structure inserted into a recess of…
Swift electrons passing near or through metallic structures have proven to be an excellent tool for studying plasmons and other types of confined optical modes involving collective charge oscillations in the materials hybridized with…
We study the electron and phonon spectral functions as well as superconductivity for a two dimensional electron gas couped to dipolar phonons via small-momentum transfer scattering. The results reported here are obtained through…
Electron localization in the Si/Ge heterosystem with Si quantum dots (QDs) was studied by transport and electron spin resonance (ESR) measurements. For Si QD structures grown on Ge(111) substrates, the ESR signal with g-factor…
Electron energy-loss spectroscopy (EELS) coupled with scanning transmission electron microscopy (STEM) is a powerful technique to determine materials composition and bonding with high spatial resolution. Noise is often a limitation…