Quasiparticle energies and optical response of RbTiOPO4 and KTiOAsO4. (23rd November 2021)

• Record Type: Journal Article
• Authors: Neufeld, S; Schindlmayr, Arno; Schmidt, W G
• Is Part Of: JPhys materials. Volume 5:Number 1(2022)
• Publication Date: 2021-11-23
• Subjects: DFT -- rubidium titanyl phosphate -- potassium titanyl arsenide -- RTP -- KTA -- GW approximation -- Bethe–Salpeter equation; Solid state physics -- Periodicals; Materials science -- Periodicals; 530.41
• DOI: 10.1088/2515-7639/ac3384
• Languages: English
• ISSNs: 2515-7639

Abstract

Abstract: 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 (RbTiOPO4 ) and potassium titanyl arsenide (KTiOAsO4 ). 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.