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Título:
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Competition between polar and nonpolar lattice distortions in oxide quantum wells: new critical thickness at polar interfaces
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Autores:
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Gázquez Alabart, J. ;
Stengel, M. ;
Mishra, R. ;
Scigaj, M. ;
Varela del Arco, María ;
Roldan, M. A. ;
Fontcuberta, J. ;
Sánchez, F. ;
Herranz, G.
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Tipo de documento:
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texto impreso
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Editorial:
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American Physical Society, 2017-09-07
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Dimensiones:
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application/pdf
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Nota general:
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info:eu-repo/semantics/openAccess
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Idiomas:
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Palabras clave:
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Estado = Publicado
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Materia = Ciencias: Física: Física de materiales
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Materia = Ciencias: Física: Física del estado sólido
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Tipo = Artículo
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Resumen:
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Two basic lattice distortions permeate the structural phase diagram of oxide perovskites: antiferrodistortive (AFD) rotations and tilts of the oxygen octahedral network and polar ferroelectric modes. With some notable exceptions, these two order parameters rarely coexist in a bulk crystal, and understanding their competition is a lively area of active research. Here we demonstrate, by using the LaAlO?/SrTiO? system as a test case, that quantum confinement can be a viable tool to shift the balance between AFD and polar modes and selectively stabilize one of the two phases. By combining scanning transmission electron microscopy (STEM) and first-principles-based models, we find a crossover between a bulklike LaAlO? structure where AFD rotations prevail, to a strongly polar state with no AFD tilts at a thickness of approximately three unit cells; therefore, in addition to the celebrated electronic reconstruction, our work unveils a second critical thickness, related not to the electronic properties but to the structural ones. We discuss the implications of these findings, both for the specifics of the LaAlO?/SrTiO? system and for the general quest towards nanoscale control of material properties.
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En línea:
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https://eprints.ucm.es/45352/1/VarelaArcoM%2008%20libre.pdf
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