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Transición del estado de espín secuencial y transferencia de carga intermetálica en PbCoO
Zhehong Liu1,2, Yuki Sakai3,4, Junye Yang1
1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Journal of the American Chemical Society
|February 22, 2020
Resumen
La alta presión induce transiciones secuenciales de estado de espín y transferencia de carga en el óxido de cobalto de plomo (PbCoO3), alterando sus propiedades eléctricas y estructurales sin dopaje químico. Este estudio revela el comportamiento único del material bajo condiciones extremas.
Área de la Ciencia:
- Ciencias de los materiales
- Física de la materia condensada
- Química del estado sólido
Sus antecedentes:
- Las transiciones de estado de espín y las transferencias de carga intermetálica son mecanismos clave para afinar las propiedades del material.
- Estos fenómenos suelen ocurrir de forma independiente, por lo que la observación secuencial es rara.
- Los óxidos de perovskita ofrecen una plataforma versátil para explorar tales efectos.
Objetivo del estudio:
- Investigar la ocurrencia secuencial de las transiciones de estado de espín y la transferencia de carga intermetálica en PbCoO3 bajo alta presión.
- Comprender el impacto de estos fenómenos acoplados en las propiedades estructurales y eléctricas del material.
- Explorar nuevas transiciones de fase de materiales impulsadas por cambios electrónicos inducidos por la presión.
Principales métodos:
- Experimentos de alta presión con el PbCoO3.
- Análisis de los cambios de estado de espín en los iones de cobalto.
- Observación de la transferencia de carga intermetálica entre los cationes de plomo y cobalto.
- Medición de la resistencia eléctrica y de las transiciones de fase estructurales.
Principales resultados:
- PbCoO3 exhibe una transición inducida por presión de alto espín a bajo espín para Co2+ de hasta 15 GPa, aumentando la resistencia.
- La transferencia de carga intermetálica entre Pb4+ y Co2+ ocurre entre 15 y 30 GPa.
- Una transición de aislante metálico y una transición de fase estructural a una fase Tetra.-I ocurren alrededor de 20 GPa.
- La compresión adicional por encima de 30 GPa conduce a una fase Tetra.-II y un comportamiento aislante reentrante.
Conclusiones:
- La presión puede inducir secuencialmente transiciones de espín y transferencia de carga en PbCoO3, lo que demuestra una nueva vía para la modulación de propiedades.
- Estos cambios electrónicos y estructurales acoplados ofrecen información sobre los diagramas de fase complejos de los óxidos de perovskita.
- Los hallazgos ponen de relieve el potencial para diseñar materiales con propiedades sintonizables a través de estímulos externos como la alta presión.
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