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Dinámica de la red y transporte térmico en semiconductores con bandas de valencia antienlace
Jiaoyue Yuan1,2, Yubi Chen1,2, Bolin Liao1
1Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, USA.
Journal of the American Chemical Society
|August 11, 2023
Resumen
Los investigadores descubrieron un nuevo método para encontrar materiales con conductividad térmica ultrabaja mediante el análisis de bandas de valencia antienlace. Este enfoque identificó más de 600 semiconductores estables, allanando el camino para materiales termoeléctricos avanzados.
Área de la Ciencia:
- Ciencias de los materiales
- Física del estado sólido
- Física de la materia condensada
Sus antecedentes:
- El alto rendimiento termoeléctrico se basa en el control de la conductividad térmica y la comprensión del transporte de fonones.
- Un desafío clave es lograr una conductividad térmica de celosía ultra baja en sólidos cristalinos.
- La identificación de nuevos materiales con conductividad térmica intrínsecamente baja es crucial para los avances tecnológicos.
Objetivo del estudio:
- Utilizar el carácter antiadherente de la banda de valencia más ocupada como descriptor para descubrir materiales con conductividad térmica ultrabaja.
- Investigar la relación entre las bandas de valencia antienlace (ABVB) y la baja conductividad térmica de la celosía.
- Identificar y analizar nuevos materiales semiconductores que exhiban una conductividad térmica ultrabaja.
Principales métodos:
- Se ha examinado el vínculo entre los ABVB y la baja conductividad térmica de celosía en sistemas modelo (PbTe, CsPbBr3).
- Realizó una búsqueda de alto rendimiento de la base de datos del Proyecto de Materiales para semiconductores binarios estables con bandas de valencia antienlace.
- Se realizó un análisis exhaustivo de los enlaces químicos y el transporte térmico en la familia XS identificada (X = K, Rb, Cs).
Principales resultados:
- Se identificaron más de 600 semiconductores binarios experimentalmente estables con un carácter de banda de valencia antienlace.
- La familia XS (metales alcalinos K, Rb, Cs) exhibió conductividades térmicas ultrabajas (< 1 W/m K)) a temperatura ambiente.
- La conductividad térmica ultrabaja se atribuyó al debilitamiento de los enlaces y al aumento de la falta de armonía de los fonones derivados de los ABVB.
Conclusiones:
- El carácter antiadherente de la banda de valencia más ocupada es un descriptor eficaz para descubrir materiales con conductividad térmica ultrabaja.
- Los hallazgos proporcionan información química sobre la dinámica de la celosía y el transporte de fonones en cristales.
- Este trabajo ofrece un enfoque práctico para el diseño racional de materiales con una conductividad térmica intrínsecamente baja.
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