Optical and excitonic properties of transition metal oxide perovskites by the Bethe-Salpeter equation

Abstract

We present a systematic investigation of the role and importance of excitonic effects on the optical properties of transitions metal oxide perovskites. A representative set of 14 compounds has been selected, including 3d

Accurate and Efficient Approximate Quasiparticle DFT‐1/2 Band Structure Calculations of Transition Metal Oxide Perovskites

“…[12], or 0.149 eV, as obtained in Ref. [27], the difference is about 0.00-0.19 eV, depending on the experimental data, showing the applicability of DFT-1/2 to this material at the same computational cost as the sdt-DFT. Related GW-results present a large dispersion depending on computational details, such as starting point, [1,15] self-consistency, [16,23,60] convergence, [1] as well as the inclusion of electron-hole interaction effects [12] and lattice polarization contributions.…”

“…[ 24 ] The exciton binding energy according to Ref. [27] is of 0.189 eV, resulting in an even better agreement between the QMC results with the experimental data.…”

“…[ 24 ] On contrast, for the , the predicts an indirect gap in the range 5.69–5.81 eV, [ 1 ] while the experimental value is 6.1–6.25 eV. [ 25,26 ] Recently, single‐shot calculations were used in a theoretical treatment of excitonic effects on such TMO perovskites, [ 27 ] showing that the exciton binding energies are in the order of hundreds of meV. Although even considering the excitonic effects some discrepancies remain.…”

Delocalization of dark and bright excitons in flat-band materials and the optical properties of V$_2$O$_5$

“…At first sight, on the basis of the Wannier model, one would not expect strong exciton binding in V 2 O 5 , with its anisotropic dielectric constant of the order of 5 51,55,56 . Indeed, for example several transitions metal oxide perovskites have similar dielectric constants and an exciton binding energy that lies rather in the range of 100-200 meV 57 . However, the rich playground of possible excitations in materials that are more complex than common semiconductors or insulators has been explored only very partially.…”

Non-Dyson Algebraic Diagrammatic Construction Theory for Charged Excitations in Solids

“…To obtain the excitedstate properties (e.g., band structure, fundamental and optical band gaps), DFT is usually combined with Green's function-based many-body perturbation theory, such as the GW approximation [5][6][7][8][9][10][11] and Bethe-Salpeter equation (BSE). [12][13][14][15][16] Although these DFT-based approaches provide important insights about the electronic structure of solids, 6,[17][18][19][20][21] their accuracy can be affected by the self-interaction error and the exchangecorrelation functional approximations inherent in DFT, 22 making the assessment of errors and systematic improvement of these methods difficult to achieve. 11,23 Recently, there has been a lot of progress in developing new, systematically improvable methods for solids by adapting the wavefunction-based theories from molecular quantum chemistry to periodic simulations of crystalline systems.…”