Functional materials: insights from experiment and theory

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Dr Emma McCabe
University of Kent
Functional materials : insights from experiment and theory E. E. McCabe a*, V. Cascos a, E. Bousquet b a School of Physical Sciences, University of Kent, Canterbury, CT2 7NH, U.K. b Université de Liège , Institut de Physique B5a, Allée du 6 Août,17, B -4000 Sart Tilman, Belgium * e.e.mccabe
Technology is developing at such a rate that the drive for new materials, to enable emerging technologies with functionalities hardly imaginable even a decade ago, has never been more exciting. 1 One class of functional materia ls that serves to illustrate this are ferroelectrics, used in piezoelectric applications and memory devices, 2 but recent developments including in photovoltaics .3-4 Traditional “proper” ferroelectrics rely on the electronic properties of particular ions. There’s been a paradigm shift in th e field with the su ggestion that a new mechanism might be capable of driving the paraelectric to ferroelectric phase transition: by this “hybrid improper” mechanism, combinations of non -polar structural distortions ( e.g. rotations of structural units) stabilise polar cation displacements. 5-6 As a result, the search for new polar materials is flourishing , particularly among classes of layered materials. Our recent work on the Dion -Jacobson family of materials has shown that its possible to tune between the two mechanisms for polar behavio ur in these systems. More recently, our combined experimental and theoretical approach has shown that in many of these layered systems, the parent high -symmetry structure can be stabilised by several distortions leading to many poss ible states of similar energies. We’ve found experimentally that this can cause disorder 7 (which might be exploited to tune properties). 8-9 The presence of metastable states e.g. in Aurivillius phases (see below) also gives the possibility to access ferroelectric and antiferroelectric phases. 10-11 This presentation highlights our recent findings from experimental and computational st udies focusing on the orgins and consequences of disorder and metastable phases. 7, 12
1. Ashley; Greenemeier , Scientific American May 2013, 2013. 2. Scott , Science 2007, 315 (5814), 954 -959. 3. Huang , Nature Photonics 2010, 4, 134 -135 . 4. Butler; Frost; Walsh , Energy Eviron. Sci. 2015, 8, 838 -848. 5. Bousquet; D awber; Stucki; Lichtensteige r; Herme t; Gariglio; Triscone; Ghosez , Nature 2008, 452 , 732 -736. 6. Benedek ; Fe nnie , Phys. Rev. Lett. 2011, 106 , 107204. 7. Casco s; Dove; Bousquet; Levin; St ennett ; Hyatt; Tra n; Halasyamani; Mc Cabe , in preparation Chem. Mater. 2019 . 8. Sto ne; Ophus; Birol; Ciston ; Le e; Wang; F ennie; Schlom; Alem; Gopalan , Nature Commun. 2016, 7, 12572. 9. Birol; Benedek; Fen nie , Phys. Rev. Lett. 2011, 107 , 257602. 10. Yoshid a; A kamatsu; Tsuji; Her nandez; Padmanabhan ; Gupta; Gibb s; Mibu; Murai; Rond inelli; Gopalan; Tanaka ; Fujita , J. Am. Chem. Soc. 2018, 140 , 15690 -15700. 11. Yoshid a; Fujita; Akamtsu; Hernande z; Gupta, A; Brown; Padmanabhan; Gibbs ; Juge; T suj i; Murai; Rondinelli; G opalan; Tanaka , Adv. Funct. Mater. 2018, 2018 , 1801856. 12. Djani ; McCabe ; Fetei ra; Zhang ; Hal asyamani; Bousquet; Ghosez , in preparation for Phys. Rev. B 2019 . b a c Illustration of non -polar ground state of an A -site deficient Aurivillius phase M2BnO3n+3, showing corner - linked BO6 octahedra in blue, and Bi and O sites in purple and red, respectively.
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  • Venue

    Theatre C, Purdie

  • Date

    October 23, 2019

  • Time

    From: 15h30 To: 16h30

  • Sponsor

    University of St Andrews
    The oldest university in Scotland, with international renown for both research and education of undergraduates and postgraduates.

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