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Transiciones estructurales de fase y superconductividad en Fe{1+delta) Se0.57Te0.43 a presiones ambientales y
Nathalie C Gresty1, Yasuhiro Takabayashi, Alexey Y Ganin
1Department of Chemistry, Durham University, Durham DH1 3LE, UK.
Journal of the American Chemical Society
|October 30, 2009
Resumen
La presión aumenta significativamente la superconductividad en los calcogenuros de hierro, con una temperatura crítica (Tc) que alcanza un máximo de 23.3 K. Un cambio estructural a la simetría monoclinica a 3 GPa se correlaciona con el Tc máximo, revelando un vínculo entre las propiedades cristalinas y electrónicas.
Área de la Ciencia:
- Física de la materia condensada Física de la materia condensada
- Ciencia de los materiales Ciencia de los materiales.
- Química del estado sólido.
Sus antecedentes:
- Los superconductores basados en Fe son una clase recientemente descubierta de materiales con propiedades únicas.
- Los calogenuros ternales del hierro, como el Fe{1.03) Se{0.57) Te{0.43), exhiben superconductividad a presiones ambiente.
- Comprender la interacción entre la estructura y la superconductividad es crucial para diseñar nuevos materiales.
Objetivo del estudio:
- Para investigar la relación entre las propiedades estructurales y electrónicas de Fe{1.03) Se{0.57) Te{0.43) bajo presión.
- Para determinar cómo la presión aplicada afecta a la temperatura crítica superconductora (T (c)).
- Para explorar las transiciones de fase estructurales inducidas por la presión.
Principales métodos:
- Se utilizó difracción de rayos X sincrotrón de alta resolución para analizar los cambios estructurales.
- La temperatura crítica superconductora (T ((c)) se midió en función de la presión aplicada.
- La estructura cristalina y la simetría se caracterizaron en varios puntos de presión.
Principales resultados:
- La temperatura crítica superconductora (T ((c)) aumentó con la presión, alcanzando un máximo de 23.3 K a aproximadamente 3 GPa.
- Una transformación estructural de la simetría ortorrómbica a la monoclinica ocurrió alrededor de 3 GPa.
- A presiones más altas (12 GPa), el material se convirtió en metálico pero perdió sus propiedades superconductoras.
Conclusiones:
- Existe un vínculo íntimo entre la estructura cristalina y las propiedades electrónicas de los superconductores de calogenuro de hierro.
- Los cambios de simetría estructural inducidos por la presión influyen directamente en el comportamiento superconductor.
- Los hallazgos proporcionan información sobre el mecanismo de superconductividad en estos materiales.
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