相关论文: Dipole matrix element approach vs. Peierls approxi…
A computational method to obtain optical conductivities from first principles is presented. It exploits a relation between the conductivity and the complex dielectric function, which is constructed from the full electronic band structure…
We present results for the optical conductivity of Na2IrO3 within density functional theory by including spin-orbit (SO) and correlation effects (U) as implemented in GGA+SO+U. We identify the various interband transitions and show that the…
Dimension reduction due to the orbital ordering has recently been proposed to explain the exotic charge, magnetic and structural transitions in some three-dimensional (3D) transitional metal oxides. We present optical measurement on a…
Core-level spectra of 1s electrons of elements heavier than Ne show significant relativistic effects. We combine advances in orbital optimized DFT (OO-DFT) with the spin-free exact two-component (X2C) model for scalar relativistic effects,…
In this first of three articles on the optical absorption of electrons in half-filled Peierls-distorted chains we present analytical results for non-interacting tight-binding electrons. We carefully derive explicit expressions for the…
In this paper we introduce an optical approximation into the theory of impedance calculation, one valid in the limit of high frequencies. This approximation neglects diffraction effects in the radiation process, and is conceptually…
We consider the impact of orbital polarons in doped orbitally ordered systems on optical conductivity using the simplest generic model capturing the directional nature of either $t_{2g}$ (or $e_g$) orbital states in certain transition metal…
The effects of quantum lattice fluctuations on the Peierls transition and the optical conductivity in the one-dimensional Holstein model of spinless fermions have been studied by developing an analytical approach, based on the unitary…
X-ray absorption spectroscopy is a well established tool for obtaining information about orbital and spin degrees of freedom in transition metal- and rare earth-compounds. For this purpose usually the dipole transitions of the L- (2p to 3d)…
We propose a novel variational method to calculate the two-hole propagators relevant for Auger spectroscopy in transition metal oxides. This method can be thought of as an intermediary step between the full solution (which is difficult to…
We describe a formally exact method to calculate the optical conductivity of a one-dimensional system with fluctuating order. For classical phase fluctuations we explicitly determine the optical conductivity by solving two coupled…
We demonstrate a new method for the direct measurement of atomic dipole transition matrix elements based on techniques developed for quantum information purposes. The scheme consists of measuring dispersive and absorptive off-resonant…
A methodology is developed to compute photoionization cross-sections beyond the electric dipole (BED) approximation from response theory, using Gaussian type orbitals and plane waves for the initial and final states, respectively. The…
We report high-pressure x-ray diffraction and magnetization measurements combined with ab-initio calculations to demonstrate that the high-pressure optical and transport transitions recently reported in TiOCl, correspond in fact to an…
We present a systematic study of the performance of numerical pseudo-atomic orbital basis sets in the calculation of dielectric matrices of extended systems using the self-consistent Sternheimer approach of [F. Giustino et al., Phys. Rev. B…
We extend in several respects our earlier work on O(p^2) corrections to matrix elements of the electroweak penguin operator O_{ewp}. First, to facilitate comparison with certain lattice studies we calculate O(p^2) corrections to…
Results of first principles augmented spherical wave electronic structure calculations for niobium dioxide are presented. Both metallic rutile and insulating low-temperature NbO2, which crystallizes in a distorted rutile structure, are…
Elemental tellurium is a strongly spin-orbit coupled Peierls-distorted semiconductor whose band structure features topologically protected Weyl nodes. Using time-dependent density functional theory calculations, we show that impulsive…
The mutual orbital alignment in multiple planetary systems is an important parameter for understanding their formation. There are a number of elaborate techniques to determine the alignment parameters using photometric or spectroscopic…
We present electron collision strengths and their thermally averaged values for the forbidden lines of the astronomically abundant doubly-ionized oxygen ion, O^{2+}, in an intermediate coupling scheme using the Breit-Pauli relativistic…