Electrochemical ferroelectric switching: Origin of polarization reversal in ultrathin films

Bristowe, N. C. and Stengel, Massimiliano and Littlewood, P. B. and Pruneda, J. M. and Artacho, Emilio (2012) Electrochemical ferroelectric switching: Origin of polarization reversal in ultrathin films. Physical Review B, 85 (2). 024106-1. ISSN 2469-9950. (doi:https://doi.org/10.1103/PhysRevB.85.024106) (Full text available)

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http://dx.doi.org/10.1103/PhysRevB.85.024106

Abstract

Against expectations, robust switchable ferroelectricity has been recently observed in ultrathin (1 nm) ferroelectric films exposed to air V. Garcia et al., Nature (London) 460, 81 (2009)]. Based on first-principles calculations, we show that the system does not polarize unless charged defects or adsorbates form at the surface. We propose electrochemical processes as the most likely origin of this charge. The ferroelectric polarization of the film adapts to the external ionic charge generated on its surface by redox processes when poling the film. This, in turn, alters the band alignment at the bottom electrode interface, explaining the observed tunneling electroresistance. Our conclusions are supported by energetics calculated for varied electrochemical scenarios.

Item Type: Article
Subjects: Q Science > QC Physics > QC173.45 Condensed Matter
Q Science > QC Physics > QC176 Solid state physics
Q Science > QD Chemistry > QD478 Solid State Chemistry
Q Science > QC Physics > QC176.8.N35 Nanoscience, nanotechnology
Q Science > QD Chemistry > QD473 Physical properties in relation to structure
Divisions: Faculties > Sciences > School of Physical Sciences
Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Nicholas Bristowe
Date Deposited: 21 Feb 2017 15:18 UTC
Last Modified: 22 Feb 2017 15:31 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/60261 (The current URI for this page, for reference purposes)
Bristowe, N. C.: https://orcid.org/0000-0003-1286-8440
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