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Formación espontánea de bandas electrónicas y comportamientos intercambiables en un cristal superatómico rico en
Evan S O'Brien1, Jake C Russell1, Matthew Bartnof2
1Department of Chemistry , Columbia University , New York , New York 10027 , United States.
Journal of the American Chemical Society
|November 13, 2018
Resumen
Los investigadores descubrieron un nuevo cristal superatómico, [Co6Te8(PEt3) [6] [C70]2, que exhibe dos transiciones de fase. Estas transiciones alteran drásticamente sus propiedades electrónicas y estructurales, ofreciendo funcionalidades sintonizables y conmutables para materiales avanzados.
Área de la Ciencia:
- Ciencias de los materiales
- Física del estado sólido
- La cristalografía
Sus antecedentes:
- Los sólidos cristalinos, como las perovskitas, exhiben diversas transiciones de fase estructurales que conducen a propiedades exóticas como la ferroelectricidad y la superconductividad.
- Los cristales superatómicos, construidos a partir de bloques programables, ofrecen propiedades ajustables y conmutables a través de transiciones de fase.
- Comprender y controlar las transiciones de fase en nuevos materiales cristalinos es clave para desarrollar funcionalidades avanzadas.
Objetivo del estudio:
- Para sintetizar y caracterizar un nuevo cristal superatómico, [Co6Te8(PEt3) [6][C70]2.
- Investigar la respuesta del material a las transiciones de fase estructurales.
- Explorar el potencial de las propiedades sintonizables y conmutables en cristales superatómicos.
Principales métodos:
- Síntesis del nuevo cristal superatómico [Co6Te8(PEt3) [6][C70]2.
- Análisis experimental de las propiedades estructurales, electrónicas y ópticas a través de transiciones de fase.
- Caracterización de los cambios en la conductividad eléctrica, la brecha óptica y la densidad de espín.
Principales resultados:
- Se observó una transición de fase estructural-electrónica acoplada, creando una nueva banda electrónica en la subtela de fullereno.
- La conductividad eléctrica aumentó en dos órdenes de magnitud, acompañada de una brecha óptica más estrecha y una mayor densidad de espín.
- Una transición orden-desorden independiente convirtió el material de un cristal de fonones en un vidrio de fonones.
Conclusiones:
- El nuevo cristal superatómico [Co6Te8(PEt3) [6] [C70]2 exhibe dos transiciones de fase distintas con modificaciones de propiedades significativas.
- Estos hallazgos demuestran una nueva clase de materiales donde las transformaciones de fase funcionales pueden ser diseñadas alterando los bloques de construcción.
- La naturaleza ajustable y conmutable de estas transiciones de fase abre caminos para el diseño de materiales funcionales avanzados.
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