by Warzanowski, P., Magnaterra, M., Stein, P., Schlicht, G., Faure, Q., Sahle, Ch. J., Lorenz, T., Becker, P., Bohatý, L., Sala, M. Moretti, Monaco, G., Van Loosdrecht, P.H.M. and Grüninger, M.
Abstract:
We demonstrate that the cubic antifluorite-type halides K2OsCl6,K2OsBr6, and Rb2OsBr6 are excellent realizations of nonmagnetic J=0 compounds. The magnetic susceptibility shows the corresponding Van Vleck type of behavior and no sign of defects. We investigate the electronic excitations with two complementary techniques, resonant inelastic x-ray scattering and optical spectroscopy. This powerful combination allows us to thoroughly study, e.g., on-site intra-t2g excitations and t2g-to-eg excitations as well as intersite excitations across the Mott gap and an exciton below the gap. In this way, we determine the electronic parameters with high accuracy, altogether yielding a comprehensive picture. In K2OsCl6, we find the spin-orbit coupling constant ζ=0.34eV, Hund’s coupling JH=0.43eV, the onset of excitations across the Mott gap at Δ=2.2 eV, the cubic crystal-field splitting 10Dq=3.3 eV, and the charge-transfer energy ΔCT=4.6 eV. With JH/ζ=1.3,K2OsCl6 is in the intermediate-coupling regime. In a t2g-only Kanamori picture, the above values correspond to ζeff=0.41eV and JHeff=0.28eV, which is very close to results reported for related 5d4 iridates. In the tetragonal phase at 5 K, the noncubic crystal field causes a peak splitting of the J=1 state as small as 4 meV. Compared to K2OsCl6, the bromides K2OsBr6 and Rb2OsBr6 show about 12-14% smaller values of 10Dq and ΔCT, while the spin-orbit entangled intra-t2g excitations below 2 eV and hence ζ and JH are reduced by less than 4%. Furthermore, the Mott gap in K2OsBr6 is reduced to about 1.8 eV. © 2023 American Physical Society.
Reference:
Electronic excitations in 5d4 J=0 Os4+ halides studied by resonant inelastic x-ray scattering and optical spectroscopy (Warzanowski, P., Magnaterra, M., Stein, P., Schlicht, G., Faure, Q., Sahle, Ch. J., Lorenz, T., Becker, P., Bohatý, L., Sala, M. Moretti, Monaco, G., Van Loosdrecht, P.H.M. and Grüninger, M.), In Physical Review B, volume 108, 2023.
Bibtex Entry:
@ARTICLE{Warzanowski2023,
author = {Warzanowski, P. and Magnaterra, M. and Stein, P. and Schlicht, G. and Faure, Q. and Sahle, Ch. J. and Lorenz, T. and Becker, P. and Bohatý, L. and Sala, M. Moretti and Monaco, G. and Van Loosdrecht, P.H.M. and Grüninger, M.},
title = {Electronic excitations in 5d4 J=0 Os4+ halides studied by resonant inelastic x-ray scattering and optical spectroscopy},
year = {2023},
journal = {Physical Review B},
volume = {108},
number = {12},
doi = {10.1103/PhysRevB.108.125120},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85173560315&doi=10.1103%2fPhysRevB.108.125120&partnerID=40&md5=fc8ddfcb7cab1e4064b34e1808b61bd8},
abstract = {We demonstrate that the cubic antifluorite-type halides K2OsCl6,K2OsBr6, and Rb2OsBr6 are excellent realizations of nonmagnetic J=0 compounds. The magnetic susceptibility shows the corresponding Van Vleck type of behavior and no sign of defects. We investigate the electronic excitations with two complementary techniques, resonant inelastic x-ray scattering and optical spectroscopy. This powerful combination allows us to thoroughly study, e.g., on-site intra-t2g excitations and t2g-to-eg excitations as well as intersite excitations across the Mott gap and an exciton below the gap. In this way, we determine the electronic parameters with high accuracy, altogether yielding a comprehensive picture. In K2OsCl6, we find the spin-orbit coupling constant ζ=0.34eV, Hund's coupling JH=0.43eV, the onset of excitations across the Mott gap at Δ=2.2 eV, the cubic crystal-field splitting 10Dq=3.3 eV, and the charge-transfer energy ΔCT=4.6 eV. With JH/ζ=1.3,K2OsCl6 is in the intermediate-coupling regime. In a t2g-only Kanamori picture, the above values correspond to ζeff=0.41eV and JHeff=0.28eV, which is very close to results reported for related 5d4 iridates. In the tetragonal phase at 5 K, the noncubic crystal field causes a peak splitting of the J=1 state as small as 4 meV. Compared to K2OsCl6, the bromides K2OsBr6 and Rb2OsBr6 show about 12-14% smaller values of 10Dq and ΔCT, while the spin-orbit entangled intra-t2g excitations below 2 eV and hence ζ and JH are reduced by less than 4%. Furthermore, the Mott gap in K2OsBr6 is reduced to about 1.8 eV. © 2023 American Physical Society.},
keywords = {Bromine compounds; Cesium compounds; Chlorine compounds; Crystals; Magnetic susceptibility; Potassium compounds; Rubidium compounds; X ray scattering; Antifluorites; Complementary techniques; Electronic excitation; Electronic parameters; High-accuracy; Mott gaps; Nonmagnetics; Optical spectroscopy; Resonant inelastic x-ray scattering; X-ray scattering spectroscopy; Charge transfer},
type = {Article},
publication_stage = {Final},
source = {Scopus},
note = {All Open Access, Green Open Access}
}
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