Structural determination and electronic properties of the 4dperovskite SrPdO3

Abstract

The structure and ground state electronic structure of the recently synthesized SrPdO3 perovskite [A. Galal et al., J. Power Sources, 195, 3806 (2010)] have been studied by means of screened hybrid functional and the GW approximation with the inclusion of electron-hole interaction within the testcharge/test-charge scheme. By conducting a structural search based on lattice dynamics and group theoretical method we identify the orthorhombic phase with Pnma space group as the most stable crystal structure. The phase transition from the ideal cubic perovskite structure to the Pnma one is explained in terms of the simultaneous stabilization of the antiferrodistortive phonon modes R + 4 and M + 3 . Our results indicate that SrPdO3 exhibits an insulating ground state, substantiated by a GW0 gap of about 1.1 eV. Spin polarized calculations suggests that SrPdO3 adopts a low spin state (t ↑↓↑↓↑↓ 2g e 0 g ), and is expected to exhibit spin excitations and spin state crossovers at finite temperature, analogous to the case of 3d isoelectronic LaCoO3. This would provide a new playground for the study of spin state transitions in 4d oxides and new opportunity to design multifunctional materials based on 4d Pnma building block.

Relativistic GW +BSE study of the optical properties of Ruddlesden-Popper iridates

“…The justification of the good performance of G 0 W 0 arises from the error cancellation stemming from the lack of self-consistency and the absence of vertex corrections [86]. However, G 0 W 0 results are clearly dependent on the starting one-electron energies and orbitals [73,85]. For systems with localized d or f states, DFT+U obtained orbitals are much closer to the ground state, and hence DFT+U are shown to be a better starting point than DFT [87,88].…”

“…This is referred to as GW+BSE. Although GW+BSE has been widely used to predict the optical spectra of various systems, e.g., molecules, clusters, semiconductors and insulators [66][67][68][69][70], its applications to TMO perovskites are very rare due to the technical challenges and the huge computational demand [71][72][73][74].…”

Cyclotron resonance of the magnetic ratchet effect and second harmonic generation in bilayer graphene

“…We excluded terms that are quadratic or higher in the magnetic field, cubic or higher in vp/γ 1 and cubic or higher in other small parameters v 4 /v, δ/γ 1 , U 1 /γ 1 and U 2 /γ 1 . Note that tight-binding models that neglect parameters v 4 and δ omit the linearin-B terms [44][45][46][47][48][49][50]. Additionally, we neglect terms that are proportional to the unit matrix in (A1, B2) space because they don't influence electronic scattering despite having a small effect on the dispersion relation.…”

Ab initio prediction of the high-pressure phase diagram of BaBiO3

“…The group-theoretical method has been successfully used to identify and predict structural distortions in a variety of perovskites 51,52 . A powerful extension is to combine this method with the results of a phonon mode analysis of the parent structure 53 . For BaBiO 3 the starting point is the ideal cubic perovskite structure - Fig.…”