Quasiparticle energies and optical response of RbTiOPO 4 and KTiOAsO 4

Many-body perturbation theory based on density-functional theory calculations is used to determine the quasiparticle band structures and the dielectric functions of the isomorphic ferroelectrics rubidium titanyl phosphate (RbTiOPO 4 ) and potassium titanyl arsenide (KTiOAsO 4 ). Self-energy correcti...

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Bibliographic Details
Published in:JPhys materials 2022-01, Vol.5 (1), p.15002
Main Authors: Neufeld, S, Schindlmayr, Arno, Schmidt, W G
Format: Article
Language:English
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Summary:Many-body perturbation theory based on density-functional theory calculations is used to determine the quasiparticle band structures and the dielectric functions of the isomorphic ferroelectrics rubidium titanyl phosphate (RbTiOPO 4 ) and potassium titanyl arsenide (KTiOAsO 4 ). Self-energy corrections of more than 2 eV are found to widen the transport band gaps of both materials considerably to 5.3 and 5.2 eV, respectively. At the same time, both materials are characterized by strong exciton binding energies of 1.4 and 1.5 eV, respectively. The solution of the Bethe–Salpeter equation based on the quasiparticle energies results in onsets of the optical absorption within the range of the measured data.
ISSN:2515-7639
2515-7639
DOI:10.1088/2515-7639/ac3384