Type

Journal Article

Authors

Roger W. Whatmore
Jonathan N Coleman
Andrew J. Bell
Michael Schmidt
Meghdad Palizdar
Ronan J Smith
Lynette Keeney

Subjects

Physics

Topics
semiconductors ferroelectric materials ultra thin electronic 2d materials ferroelectrics scaling law time domain piezoresponse force microscopy

Ferroelectric behavior in exfoliated 2D Aurivillius oxide flakes of sub-unit cell thickness (2020)

Abstract Ferroelectricity in ultrasonically exfoliated flakes of the layered Aurivillius oxide Bi5Ti3Fe0.5Co0.5O15 with a range of thicknesses is studied. These flakes have relatively large areas (linear dimensions many times the film thickness), thus classifying them as 2D materials. It is shown that ferroelectricity can exist in flakes with thicknesses of only 2.4 nm, which equals one‐half of the normal crystal unit cell. Piezoresponse force microscopy (PFM) demonstrates that these very thin flakes exhibit both piezoelectric effects and that the ferroelectric polarization can be reversibly switched. A new model is presented that permits the accurate modeling of the field‐on and field‐off PFM time domain and hysteresis loop responses from a ferroelectric during switching in the presence of charge injection, storage, and decay through a Schottky barrier at the electrode–oxide interface. The extracted values of spontaneous polarization, 0.04(±0.02) C m−2 and electrostrictive coefficient, 2(±0.1) × 10−2 m4 C−2 are in good agreement with other ferroelectric Aurivillius oxides. Coercive field scales with thickness, closely following the semi‐empirical scaling law expected for ferroelectric materials. This constitutes the first evidence for ferroelectricity in a 2D oxide material, and it offers the prospect of new devices that might use the useful properties associated with the switchable ferroelectric spontaneous polarization in a 2D materials format.
Collections Ireland -> University College Cork -> College of Science, Engineering and Food Science
Ireland -> University College Cork -> Tyndall National Institute
Ireland -> University College Cork -> Tyndall National Institute - Journal Articles
Ireland -> University College Cork -> Chemistry
Ireland -> University College Cork -> Chemistry - Journal Articles
Ireland -> University College Cork -> Research Institutes and Centres

Full list of authors on original publication

Roger W. Whatmore, Jonathan N Coleman, Andrew J. Bell, Michael Schmidt, Meghdad Palizdar, Ronan J Smith, Lynette Keeney

Experts in our system

1
Roger W. Whatmore
University College Cork
Total Publications: 23
 
2
Jonathan Coleman
Trinity College Dublin
Total Publications: 217
 
3
Michael Schmidt
University College Cork
Total Publications: 42
 
4
Ronan J Smith
Trinity College Dublin
Total Publications: 11
 
5
Lynette Keeney
University College Cork
Total Publications: 22