El metal osmio más incompresible a presiones estáticas por encima de 750 gigapascales
L Dubrovinsky1, N Dubrovinskaia2, E Bykova1,2
1Bavarian Research Institute of Experimental Geochemistry and Geophysics, University of Bayreuth, D-95440 Bayreuth, Germany.
Nature
|August 25, 2015
Resumen
El osmio metálico (Os) permanece hexagonalmente compactado hasta 770 gigapascales. Las anomalías en su relación de parámetros de la célula unitaria sugieren transiciones electrónicas, incluidas las interacciones de electrones del núcleo bajo presión extrema.
Área de la Ciencia:
- Ciencias de los materiales
- Física de la materia condensada
- Física de altas presiones
Sus antecedentes:
- El osmio metálico (Os) posee propiedades excepcionales como alta densidad y temperatura de fusión.
- Su comportamiento bajo alta presión se entiende mal, con estudios limitados a menos de 75 gigapascales.
Objetivo del estudio:
- Para investigar el comportamiento de alta presión del osmio metálico utilizando técnicas experimentales avanzadas.
- Comprender las transiciones estructurales y electrónicas del osmio bajo presiones de varios megabares.
Principales métodos:
- Mediciones de difracción de rayos X en polvo de osmio utilizando células de yunque de diamante.
- Determinación precisa de la presión a través de ecuaciones de estado autoconsistentes para oro, platino y tungsteno hasta 500 gigapascales.
- Cálculos de la teoría del campo medio dinámico.
Principales resultados:
- El osmio conserva su estructura hexagonal hasta 770 gigapascales.
- Se observaron anomalías en la relación de parámetros de la célula unitaria alrededor de 150 y 440 gigapascales.
- La anomalía de 150 gigapascales está vinculada a los cambios topológicos de la superficie de Fermi; la anomalía de 440 gigapascales puede involucrar interacciones de electrones del núcleo.
Conclusiones:
- Los experimentos de alta presión revelan un comportamiento estructural y electrónico complejo en el osmio.
- Las interacciones de electrones del núcleo inducidas por presión en metales incompresibles son posibles.
- Esta investigación abre caminos para explorar nuevos estados de la materia bajo extrema compresión.
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