Pseudopotential Bethe-Salpeter calculations for shallow-core x-ray absorption near-edge structures: excitonic effects in Al2O3

Abstract

We present an ab initio description of optical and shallow-core x-ray absorption spectroscopies in a unified formalism based on the pseudopotential plane-wave method at the level of the Bethe-Salpeter equation (BSE) within Green's functions theory. We show that norm-conserving pseudopotentials are reliable and accurate not only for valence, but also for semicore electron excitations. In order to validate our approach, we compare BSE absorption spectra obtained with two different codes: the pseudopotential-based code EXC and the all-electron full-potential code Exciting. We take corundum $\alpha$-Al${}_2$O${}_3$ as an example, being a prototypical material that presents strong electron-hole interactions for both valence and core electron excitations. We analyze in detail the optical absorption spectrum as well as the Al L${}_1$ and L${}_{2,3}$ edges in terms of anisotropy, crystal local fields, interference and excitonic effects. We perform a thorough inspection of the origin and localization of the lowest-energy excitons, and conclude highlighting the purely electronic character off the pre-edge of L${}_1$ and the dichroic nature of the optical and L${}_{23}$ spectra.

arXiv comment16 pages, 11 figures

References in corpus (34)

• Optimized norm-conserving Vanderbilt pseudopotentials
• The PseudoDojo: Training and grading a 85 element optimized norm-conserving pseudopotential table
• Quasiparticle Self-Consistent GW Theory
• Ab initio calculation of excitonic effects in the optical spectra of semiconductors
• Precision and efficiency in solid-state pseudopotential calculations
• Error estimates for solid-state density-functional theory predictions: an overview by means of the ground-state elemental crystals
• Multiplet ligand-field theory using Wannier orbitals
• X-ray Absorption Near-Edge Structure calculations with pseudopotentials. Application to K-edge in diamond and alpha-quartz
• Bethe-Salpeter Equation Calculations of Core Excitation Spectra
• Predictive GW calculations using plane waves and pseudopotentials
• Efficient implementation of core-excitation Bethe Salpeter equation calculations
• The Band-Gap Problem in Semiconductors Revisited: Effects of Core States and Many-Body Self-Consistency
• Band convergence and linearization error correction of all-electron GW calculations: The extreme case of zinc oxide
• Adequacy of Approximations in GW Theory
• Efficient $\mathcal{O}(N^2)$ approach to solve the Bethe-Salpeter equation for excitonic bound states
• Effect of Semicore Orbitals on the Electronic Band Gaps of Si, Ge, and GaAs within the GW Approximation
• Norm-conserving pseudopotentials with chemical accuracy compared to all-electron calculations
• Projector augmented wave calculation of x-ray absorption spectra at the L2,3 edges
• Elimination of the linearization error in GW calculations based on the linearized augmented-plane-wave method
• Accurate X-Ray Absorption Predictions for Transition Metal Oxides: An Advanced Self-Consistent-Field Approach Inspired by Many-Body Perturbation Theory
• Reproducibility in $G_0{W}_0$ Calculations for Solids
• Addressing electron-hole correlation in core excitations of solids: An all-electron many-body approach from first principles
• Experimental evidence of thermal fluctuations on the X-ray absorption near-edge structure at the aluminum K-edge
• Effect of vibrations on the pre-edge features of x-ray absorption spectra
• Cumulant Green's function calculations of plasmon satellites in bulk sodium: influence of screening and the crystal environment
• Demonstration of resonant inelastic X-ray scattering as a probe of exciton-phonon coupling
• Description of resonant inelastic x-ray scattering in correlated metals
• Probing electron-phonon interactions away from the Fermi level with resonant inelastic x-ray scattering
• Excitation Pathways in Resonant Inelastic X-Ray Scattering of Solids
• Screening in YBCO at large wave vectors
• All-electron many-body approach to resonant inelastic x-ray scattering
• First-principles study of excitons in the optical spectra of silver chloride
• Robustness of electronic screening effects in electron spectroscopies: example of V${}_2$O${}_5$
• Dynamical screening in SrVO${}_3$: Inelastic x-ray scattering experiments and ab initio calculations

Cited by in corpus (1)

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