Permittivity boosting by induced strain from local doping in titanates from first principles.
Sci Rep
; 13(1): 3761, 2023 Mar 07.
Article
in En
| MEDLINE
| ID: mdl-36882507
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 εion ~ 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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Type of study:
Prognostic_studies
Language:
En
Journal:
Sci Rep
Year:
2023
Document type:
Article
Affiliation country:
Japan