Electrically tunable dielectric thin films in active circuits and systems are challenged by capacitance-induced delays and impedance matching requiring a lower dielectric constant. Here an approach to increasing the intrinsic tunability of compounds containing TiO6 octahedra by considering the influence of different connectivity among these octahedra is presented. Such connectivity variants in nanocrystalline monoclinic BaTi2O5 thin films enable a two orders of magnitude enhancement in Ti anharmonic interaction, thereby permitting a ≈65% decrease in dielectric constant to 70 at room temperature without sacrificing tunability. Edge-sharing TiO6 octahedra possess a much shorter Ti-Ti distance of only 2.91 Å as compared to the perovskite structure (~4 Å), permitting large field-induced structural re-arrangement and intrinsic tunability.
|State||Published - 15 Apr 2021|
Bibliographical noteFunding Information:
The authors thank Adrian Podpirka and Alejandro Gutierrez-Perez for assistance with device processing and data collection. Work at Drexel University was supported by the Army Research Laboratory under Cooperative Agreement No. W911-NF-19-2-0119, the Office of Naval Research under grant N00014-15-11-2170 , and the National Science Foundation under CBET 1705440 . We acknowledge the core shared user facilities at Drexel University under NSF DMR 1040166, and Picosun Oy (Finland) for support.
- Atomic layer deposition
- BaTiO thin films
- Density functional theory
- Dielectric properties