Hybrid cluster-expansion and density-functional-theory approach for optical absorption in TiO2

Abstract

A combined approach of first-principles density-functional calculations and the systematic cluster-expansion scheme is presented. The dipole, quadrupole, and Coulomb matrix elements obtained from ab initio calculations are used as an input to the microscopic many-body theory of the excitonic optical response. To demonstrate the hybrid approach for a nontrivial semiconductor system, the near-bandgap excitonic optical absorption of rutile TiO2 is computed. Comparison with experiments yields strong evidence that the observed near-bandgap features are due to a dipole-forbidden but quadrupole-allowed 1s-exciton state.

arXiv comment14 pages, 4 figures

References in corpus (15)

• Electronic Structure Calculations with Dynamical Mean-Field Theory: A Spectral Density Functional Approach
• Frequency-dependent local interactions and low-energy effective models from electronic structure calculations
• Self-Energy and Excitonic Effects in the Electronic and Optical Properties of TiO2 Crystalline Phases
• Band engineering in dilute nitride and bismide semiconductor lasers
• Efficient $\mathcal{O}(N^2)$ approach to solve the Bethe-Salpeter equation for excitonic bound states
• Exciton-plasmon states in nanoscale materials: breakdown of the Tamm-Dancoff approximation
• Quasiparticle level alignment for photocatalytic interfaces
• Strong renormalization of the electronic band gap due to lattice polarization in the GW formalism
• Intensity fluctuations in bimodal micropillar lasers enhanced by quantum-dot gain competition
• Extraction of many-body configurations from nonlinear absorption in semiconductor quantum wells
• Derivation of Static Low-Energy Effective Models by ab initio Downfolding Method without Double Counting of Coulomb Correlations: Application to SrVO3, FeSe and FeTe
• Few-photons model of the optical emission of semiconductor quantum dots
• Hyperbolic Bloch equations: atom-cluster kinetics of an interacting Bose gas
• Excitation picture of an interacting Bose gas
• Excitonic terahertz absorption in semiconductors with effective-mass anisotropies