Permittivity boosting by induced strain from local doping in titanates from first principles

Autor: Alex Kutana, Yuho Shimano, Ryoji Asahi
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Scientific Reports, Vol 13, Iss 1, Pp 1-7 (2023)
Druh dokumentu: article
ISSN: 2045-2322
DOI: 10.1038/s41598-023-30965-6
Popis: Abstract We examine the effect of isovalent substitutions and co-doping on the ionic dielectric constant of paraelectric titanates (perovskite, Ruddlesden-Popper phases, and rutile) using density functional perturbation theory. Substitutions increase the ionic dielectric constant of the prototype structures, and new dynamically stable structures with ε ion ~ 102–104 are reported and analyzed. The boosting of ionic permittivity is attributed to local defect-induced strain, and maximum Ti–O bond length is proposed as a descriptor. The Ti–O phonon mode that is responsible for the large dielectric constant can be tuned by a local strain and symmetry lowering from substitutions. Our findings help explain the recently observed colossal permittivity in co-doped rutile, attributing its intrinsic permittivity boosting solely to the lattice polarization mechanism, without the need to invoke other mechanisms. Finally, we identify new perovskite- and rutile-based systems that can potentially display colossal permittivity.
Databáze: Directory of Open Access Journals
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