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Un interruptor de simetría ultrarrápido en un semimetal de Weyl
Edbert J Sie1,2, Clara M Nyby3, C D Pemmaraju2
1Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, USA.
Nature
|January 4, 2019
Resumen
Los investigadores utilizaron pulsos de luz de terahertz para inducir una tensión de corte ultrarrápida en WTe2, creando una nueva fase topológica. Este avance permite la manipulación de alta velocidad de las propiedades topológicas para futuros dispositivos electrónicos.
Área de la Ciencia:
- Física de la materia condensada
- Ciencias de los materiales
- Los fenómenos cuánticos
Sus antecedentes:
- Los materiales cuánticos topológicos poseen propiedades únicas cruciales para la electrónica avanzada y la computación cuántica.
- El control de las invariantes topológicas es clave para el desarrollo de aplicaciones de conmutación topológica.
- La tensión de la red es un método primario para ajustar los invariantes topológicos, pero los métodos convencionales carecen de control dinámico.
Objetivo del estudio:
- Investigar el potencial de los pulsos de luz en terahercios (THz) para inducir y manipular propiedades topológicas en materiales cuánticos.
- Explorar la creación de protocolos de deformación variables en el tiempo para la conmutación topológica ultra rápida.
- Demostrar la viabilidad de un conmutador topológico que funcione a frecuencias THz.
Principales métodos:
- Utilizó la difracción de electrones relativista para las mediciones cristalográficas.
- Se emplean pulsos de luz de terahertz para inducir la tensión de corte entre capas en WTe2.
- Se han realizado mediciones ópticas no lineales para caracterizar las transiciones de fase y los cambios de simetría.
Principales resultados:
- Se ha demostrado la tensión de corte entre capas de frecuencia THz con gran amplitud en WTe2.
- Inducido una transición de fase metastable topológicamente distinta a través de la cepa inducida por THz.
- Se observó un cambio de simetría a una fase centrosimétrica, topológicamente trivial.
- Muestra inducción ultra rápida o aniquilación de puntos de Weyl con quiralidad opuesta.
Conclusiones:
- Los pulsos de luz THz pueden inducir una deformación de corte ultra rápida y de gran amplitud en materiales topológicos.
- Esta cepa permite la manipulación dinámica de los estados topológicos, lo que lleva a distintas fases metastables.
- Los hallazgos allanan el camino para el desarrollo de interruptores topológicos ultrarrápidos que funcionan a frecuencias THz.
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