The modern version of the KKR (Korringa–Kohn–Rostoker) method represents the electronic structure of a system directly and efficiently in terms of its single-particle Green's function (GF). This is in contrast to its original version and many other traditional wave-function-based all-electron band structure methods dealing with periodically ordered solids. Direct access to the GF results in several appealing features. In addition, a wide applicability of the method is achieved by employing multiple scattering theory. The basic ideas behind the resulting KKR-GF method are outlined and the different techniques to deal with the underlying multiple scattering problem are reviewed. Furthermore, various applications of the KKR-GF method are reviewed in some detail to demonstrate the remarkable flexibility of the approach. Special attention is devoted to the numerous developments of the KKR-GF method, that have been contributed in recent years by a number of work groups, in particular in the following fields: embedding schemes for atoms, clusters and surfaces, magnetic response functions and anisotropy, electronic and spin-dependent transport, dynamical mean field theory, various kinds of spectroscopies, as well as first-principles determination of model parameters.

https://iopscience.iop.org/article/10.1088/0034-4885/74/9/096501/pdf

Calculating condensed matter properties using the KKR-Green's function method—recent developments and applications

Lithium-ion battery packs in hybrid and electric vehicles, as well as in other traction applications, are always equipped with a Battery Management System (BMS). The BMS consists of hardware and software for battery management including, among others, algorithms determining battery states. The accurate and reliable State of Health (SOH) estimation is a challenging issue and it is a core factor of a battery energy storage system. In this paper, battery SOH monitoring methods are reviewed. To this end, different scientific and technical literature is studied and the respective approaches are classified in specific groups. The groups are organized in terms of the way the method is carried out: Experimental Techniques or Adaptive Models. Not only strengths and weaknesses for the use in online BMS applications are reviewed but also their accuracy and precision is studied. At the end of the document a potential, new and promising via in order to develop a methodology to estimate the SOH in real applications is detailed.

Critical review of state of health estimation methods of Li-ion batteries for real applications

Gold surfaces host special electronic states that have been understood as a prototype of Shockley surface states. These surface states are commonly employed to benchmark the capability of angle-resolved photoemission spectroscopy (ARPES) and scanning tunnelling spectroscopy. Here we show that these Shockley surface states can be reinterpreted as topologically derived surface states (TDSSs) of a topological insulator (TI), a recently discovered quantum state. Based on band structure calculations, the Z2-type invariants of gold can be well-defined to characterize a TI. Further, our ARPES measurement validates TDSSs by detecting the dispersion of unoccupied surface states. The same TDSSs are also recognized on surfaces of other well-known noble metals (for example, silver, copper, platinum and palladium), which shines a new light on these long-known surface states. The surfaces of noble metals possess Shockley states which exhibit Rashba-type spin splitting and spin-momentum locking. Here, the authors use ab initiomethods and photoemission spectroscopy to demonstrate how such Shockley states may be reinterpreted as topologically protected surface states.

/pdf/topological-states-on-the-gold-surface-uh8cmlajo6.pdf

Topological states on the gold surface

The surfaces of bismuth: Structural and electronic properties

The generalization of the Local Density Approximation (LDA) method for the systems with strong Coulomb correlations is presented which gives a correct description of the Mott insulators. The LDA+U method is based on the model hamiltonian approach and allows to take into account the non-sphericity of the Coulomb and exchange interactions. parameters. Orbital-dependent LDA+U potential gives correct orbital polarization and corresponding Jahn-Teller distortion. To calculate the spectra of the strongly correlated systems the impurity Anderson model should be solved with a many-electron trial wave function. All parameters of the many-electron hamiltonian are taken from LDA+U calculations. The method was applied to NiO and has shown good agreement with experimental photoemission spectra and with the oxygen Kα X-ray emission spectrum.

http://absimage.aps.org/image/MAR06/MWS_MAR06-2005-007233.pdf

First-principles calculations of electronic structure and spectra of strongly correlated systems: the LDA+U method

We present a comprehensive photoemission study of the L-gap surface states of the (111) surfaces of Cu, Ag, and Au by high-resolution angle-resolved photoelectron spectroscopy (PES). With an angular resolution of about $\ensuremath{\Delta}\ensuremath{\theta}=\ifmmode\pm\else\textpm\fi{}0.15\ifmmode^\circ\else\textdegree\fi{}$ and an energy resolution of $\ensuremath{\Delta}E\ensuremath{\approx}3.5\mathrm{meV},$ our data establish new values for the intrinsic lifetime broadening and the dispersion relation of these surface states. We compare our photoemission results to recently published theoretical calculations and measurements by scanning tunneling spectroscopy (STS). In the case of the Au(111) state, we observe particular qualitative discrepancies in comparison to the STS data: the PES data show a split dispersion and Fermi surface, possibly caused by a spin-orbit interaction of the surface state electrons.

Direct measurements of the L -gap surface states on the (111) face of noble metals by photoelectron spectroscopy

We present high-resolution photoemission spectroscopy studies on the Kondo resonance of the strongly correlated Ce system ${\mathrm{CeCu}}_{2}{\mathrm{Si}}_{2}$. By exploiting the thermal broadening of the Fermi edge we analyze position, spectral weight, and temperature dependence of the low-energy $4f$ spectral features, whose major weight lies above the Fermi level ${E}_{F}$. We also present theoretical predictions based on the single-impurity Anderson model using an extended noncrossing approximation, including all spin-orbit and crystal field splittings of the $4f$ states. The excellent agreement between theory and experiment provides strong evidence that the spectral properties of ${\mathrm{CeCu}}_{2}{\mathrm{Si}}_{2}$ can be described by single-impurity Kondo physics down to $T\ensuremath{\approx}5\mathrm{K}$.

Temperature dependence of the Kondo resonance and its satellites in CeCu2Si2.

An ovel instrument for imaging ESCA is described. It is based on a tandem arrangement of two hemispherical energy analysers used as an imaging energy filter. The main spherical aberration (α 2 -term) of the analyser is corrected by the antisymmetry of the tandem configuration. The kinetic energy range useable for imaging extends up to 1.6 keV; this is compatible with Mg and Al Kα laboratory x-ray sources. First experiments on the chemical surface composition of a Cu0.98Bi0.02 polycrystal, a GaAs/AlGaAs heterostructure and Ag crystallites on Si(111) have been performed using synchrotron radiation. The results reveal an energy resolutio no f190 meV and a lateral resolution (edge resolution) of 120 nm. Besides elimination of the analyser’s spherical aberration, the tandem arrangement largely retains the time structure of the electron signal, unlike a singl eh emispherical analyser.

http://iopscience.iop.org/article/10.1088/0953-8984/17/16/004/pdf

Nanoelectron spectroscopy for chemical analysis: a novel energy filter for imaging x-ray photoemission spectroscopy

We present a systematic study of the change in work function of noble metal (111) surfaces (Cu, Ag, Au) when being covered with a monolayer of a rare gas (Ar, Kr, Xe). Using a Kelvin probe the experiments show a decrease of the work function of the adsorbate covered system compared to the clean metal surface, in agreement with physisorption theory. The difference in work function depends both on the substrate and adsorbate being the highest for the $\mathrm{Xe}∕\mathrm{Cu}$ system and the lowest for $\mathrm{Ar}∕\mathrm{Au}$. A comparison is performed with angle-resolved ultraviolet photoemission spectroscopy data using the binding energy shift of the (111) surface states of the same adsorbate/substrate systems, and with density functional calculations on simple model systems.

S. Schmidt

Papers

Direct measurements of the L -gap surface states on the (111) face of noble metals by photoelectron spectroscopy

Temperature dependence of the Kondo resonance and its satellites in CeCu2Si2.

Nanoelectron spectroscopy for chemical analysis: a novel energy filter for imaging x-ray photoemission spectroscopy

Work function studies of rare-gas/noble metal adsorption systems using a Kelvin probe

Surface and interface states on adsorbate covered noble metal surfaces