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Ferroelectricidad en grupos de niobio libre.
Ramiro Moro1, Xiaoshan Xu, Shuangye Yin
1School of Physics, Georgia Institute of Technology, Atlanta GA, 30332-0430, USA.
Science (New York, N.Y.)
|May 24, 2003
Resumen
Los cúmulos fríos de niobio exhiben momentos de dipolo eléctrico anómalos y grandes, un estado parecido al ferroeléctrico que no se ve a temperatura ambiente. Este descubrimiento en materia metálica puede estar relacionado con la superconductividad.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Física de la materia condensada Física de la materia condensada
- Química cuántica es la química cuántica.
Sus antecedentes:
- Los grupos de niobio neutro (NbN) exhiben propiedades eléctricas dependientes de la temperatura.
- Las mediciones de temperatura ambiente muestran polarizabilidades metálicas normales.
Objetivo del estudio:
- Investigar los momentos de dipolo eléctrico de los cúmulos de niobio enfriados criogénicamente.
- Caracteriza la transición a un estado parecido al ferroeléctrico en grupos metálicos.
Principales métodos:
- Mediciones de la deflexión eléctrica de los grupos de niobio en fase gaseosa (N=2-150) en haces moleculares.
- Control de temperatura variable (20-300 Kelvin) para observar las transiciones de fase.
Principales resultados:
- Los grupos fríos de niobio (NbN) muestran momentos de dipolo eléctrico anómalos y grandes por debajo de una temperatura de transición TG (N).
- Un estado parecido al ferroeléctrico se desarrolla en grupos de NbN a bajas temperaturas.
- TG(N) disminuye con el aumento del tamaño del racimo (N), mostrando alternancias impares para N > 38.
Conclusiones:
- Existe un nuevo estado de materia metálica con propiedades parecidas a las ferroeléctricas en grupos fríos de niobio.
- Este fenómeno puede estar relacionado con la superconductividad a granel en los materiales de niobio.
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