High dielectric tunability in ferroelectric-paraelectric bilayers and multilayer superlattices

摘要

The dielectric tunability of ferroelectric/paraelectric bilayers and multilayer superlattices are examined theoretically. A numerical analysis is carried out for a pseudomorphic (001) BaTiO_3/SrTiO_3 heteroepitaxial bilayer on (001) SrTiO_3 and a stress-free BaTiO_3/SrTiO_3 bilayer. We show that these structures are capable of tunabilities greater than 90% due to electrostatic and electromechanical coupling between layers. Moreover, we develop the methodology for incorporation conventional integrated circuit silicon dielectrics into heteroepitaxial structures that can reduce current leakage while maintaining high tunability, thereby enabling the device designer flexibility toward the optimization of microwave and millimeter wave elements.