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Electromechanical Manipulation of Topological Defects to Yield Giant Piezoelectric Response in Epitaxial Lead Zirconate Titanate Bilayers on Silicon
Author(s) -
Winkler Richard Stephen,
Zhang Yangyang,
Zhang Qi,
Wang Zhe,
Zhu Yimei,
Han MyungGeun,
Schlom Darrell G.,
Valanoor Nagarajan
Publication year - 2021
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.202100195
Subject(s) - materials science , bilayer , tetragonal crystal system , ferroelectricity , epitaxy , silicon , condensed matter physics , substrate (aquarium) , lead zirconate titanate , optoelectronics , topology (electrical circuits) , nanotechnology , crystallography , layer (electronics) , dielectric , crystal structure , membrane , electrical engineering , engineering , chemistry , genetics , physics , oceanography , geology , biology
The combination of topological defect mobility and exploitation of the boundary conditions in bilayer heterostructures presents an enormous opportunity for enhancing actuation responses from modest external stimuli in electromechanical applications. Tetragonal PbZr 0.3 Ti 0.7 O 3 and underlying rhombohedral PbZr 0.54 Ti 0.46 O 3 ferroelectric bilayers are epitaxially grown on silicon substrates. The topmost layer shows crystallographic symmetry lower than a typical tetragonal structure but is arranged in‐plane with a mosaic pattern of superdomains and ferroelastic a 1/ a 2 nanodomains within. The domain pattern also shows a series of vortex/anti‐vortex pairs induced in the pseudo‐tetragonal film, which can be manipulated to either migrate across the film or annihilate one another in the presence of an external electrical bias. The mobility of defect pairs and domain walls, through reduced substrate clamping by the underlying rhombohedral film, is the driving force for endowing the bilayer with a ≈45% increased effective d 33 response compared to a rhombohedral single layer on silicon. Furthermore, a square in‐plane polarization loop (≈32 µC cm –2 ) provides further evidence of the mobility and large‐scale polarization switching. An improvement of this magnitude demonstrates the opportunity to implement bilayer technology while exploiting a functional silicon substrate for enhanced, industry‐ready, smart material applications.