On the persistence of polar domains in ultrathin ferroelectric capacitors
Zubko, Pavlo (University College London)
Lu, Haidong (University of Nebraska-Lincoln)
Bark, C. W. (University of Wisconsin-Madison. Department of Materials Science and Engineering)
Martí Rovirosa, Xavier (Academy of Sciences of the Czech Republic)
Santiso, José (Institut Català de Nanociència i Nanotecnologia)
Eom, Chang-Beom (University of Wisconsin-Madison. Department of Materials Science and Engineering)
Catalan, Gustau (Institut Català de Nanociència i Nanotecnologia)
Gruverman, A. (University of Nebraska-Lincoln. Department of Physics and Astronomy)

Date:	2017
Abstract:	The instability of ferroelectric ordering in ultra-thin films is one of the most important fundamental issues pertaining realization of a number of electronic devices with enhanced functionality, such as ferroelectric and multiferroic tunnel junctions or ferroelectric field effect transistors. In this paper, we investigate the polarization state of archetypal ultrathin (several nanometres) ferroelectric heterostructures: epitaxial single-crystalline BaTiO films sandwiched between the most habitual perovskite electrodes, SrRuO, on top of the most used perovskite substrate, SrTiO. We use a combination of piezoresponse force microscopy, dielectric measurements and structural characterization to provide conclusive evidence for the ferroelectric nature of the relaxed polarization state in ultrathin BaTiO capacitors. We show that even the high screening efficiency of SrRuO electrodes is still insufficient to stabilize polarization in SrRuO/BaTiO/SrRuO heterostructures at room temperature. We identify the key role of domain wall motion in determining the macroscopic electrical properties of ultrathin capacitors and discuss their dielectric response in the light of the recent interest in negative capacitance behaviour.
Grants:	Ministerio de Economía y Competitividad FIS2013-48668-C2-1-P
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Ferroelectric domains ; Negative capacitance ; Polarization screening ; Retention ; Tunnel junctions ; Ultrathin barium titanate
Published in:	Journal of Physics Condensed Matter, Vol. 29, Núm. 28 (July 2017) , art. 284001, ISSN 1361-648X

DOI: 10.1088/1361-648X/aa73c3

9 p, 1.8 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
Articles > Research articles
Articles > Published articles