Phase Boundary Enabled High Dielectric Tunability in Ba <sub>1</sub> <sub>−</sub> <sub>x</sub> Sr <sub>x</sub> TiO <sub>3</sub> Thin Films and their Integration on Silicon
(BST; x = 0.2-0.8) epitaxial thin films. Through systematic control of composition and epitaxial strain, we have experimentally revealed the coexistence of cubic, tetragonal, rhombohedral, and orthorhombic phases, forming a mixed-phase state analogous to a morphotropic phase boundary (MPB). This phase coexistence results in exceptional dielectric properties, including ultra-high tunability (∼91%) and a high breakdown electric field (∼800 kV/cm) at room temperature (10 kHz). The films exhibit good thermal (from 330 to 473 K) and frequency (10 kHz-1 MHz) stability. The robust dielectric tunability being associated with a diffuse-phase transition at higher strontium concentrations, arising from dipole dispersion, leading to relaxor-like behavior. Theoretical studies using effective-Hamiltonian approaches confirm the emergence of the MPB-like state and its role in enhanced dielectric permittivity and tunability. Finally, integration of these BST thin films onto silicon is demonstrated, highlighting the potential for scalability. These findings bridge the gap between material innovation and industrial implementation.
Authors
- Sankalpa Hazra (ORCID: https://orcid.org/0000-0002-9126-8058)
- Venkatraman Gopalan (ORCID: https://orcid.org/0000-0001-6866-3677)
- Sujit Das (ORCID: https://orcid.org/0000-0001-9823-0207)
- Sukriti Mantri (ORCID: https://orcid.org/0000-0002-8149-7869)
- Lane W. Martin (ORCID: https://orcid.org/0000-0003-1889-2513)
- S. B. Krupanidhi (ORCID: https://orcid.org/0000-0001-6393-0908)
- Yangyang Si (ORCID: https://orcid.org/0009-0009-7770-4210)
- Zuhuang Chen (ORCID: https://orcid.org/0000-0003-1912-6490)
- S F Chen
- Basanta Roul (ORCID: https://orcid.org/0000-0001-7749-6698)
- Manuel Valvidares (ORCID: https://orcid.org/0000-0003-4895-8114)
- Deepak Prajapat (ORCID: https://orcid.org/0000-0002-6269-8382)
- Sourav Chowdhury (ORCID: https://orcid.org/0000-0003-3965-002X)
- Garima Kaura (ORCID: https://orcid.org/0009-0006-2123-8175)
- Fang Liu
- Laurent Bellaiche
- Akash Saha
- Yun‐Long Tang
Institutions
- Bharat Electronics (India) (IN)
- Pennsylvania State University (US)
- Shenyang University of Technology (CN)
- Tel Aviv University (IL)
- Harbin Institute of Technology (CN)
- ALBA Synchrotron (Spain) (ES)
- Deutsches Elektronen-Synchrotron DESY (DE)
- Institute of Metal Research (CN)
- Indian Institute of Science Bangalore (IN)
- Rice University (US)
- University of Arkansas at Fayetteville (US)
Publication Details
- Journal
- Advanced Materials
- Published
- 2026-04-21
- DOI
- https://doi.org/10.1002/adma.73172
- Primary Topic
- Ferroelectric and Piezoelectric Materials
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- Indian Institute of Science
- Arkansas Economic Development Commission
- National Natural Science Foundation of China