Generación ultrarrápida de campo pseudo-magnético para excitones de valle en monocapas de WSe2

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Jonghwan Kim¹, Xiaoping Hong¹, Chenhao Jin¹

¹Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA.

Science (New York, N.Y.)

|December 6, 2014

Resumen

Los investigadores generaron un campo seudomagnético de valle ultrarrápido en materiales 2D (MX2) utilizando luz polarizada circularmente. Este avance permite el control selectivo del grado de libertad del valle para potenciales aplicaciones de información cuántica.

Área de la Ciencia:

Física de la materia condensada Física de la materia condensada
Ciencia de los materiales Ciencia de los materiales.
Ciencias de la información cuántica Ciencias de la información cuántica.

Sus antecedentes:

El pseudospin del valle es un grado de libertad emergente en los dicalcogenuros de metales de transición 2D (MX2).
El control sobre el pseudospin del valle ofrece potencial para nuevas aplicaciones inspiradas en la espintrónica.
Los métodos existentes para la manipulación del valle son limitados.

Objetivo del estudio:

Para demostrar la generación de un campo seudomagnético de valle ultrarrápido y ultraalto en monocapa MX2.2.
Para lograr un control selectivo del grado de libertad del valle utilizando pulsos ópticos.
Explorar las posibles aplicaciones en el procesamiento de información cuántica.

Principales métodos:

Utilizó pulsos láser de femtosegundo circularmente polarizados para la excitación óptica.
Empleó espectroscopia de bomba-sonda ultrarrápida para sondear la dinámica del valle.
Investigó el deselenido de tungsteno monocapa (WSe2) como el sistema de materiales.

Principales resultados:

Generó con éxito un efecto Stark óptico selectivo de valle ultra rápido en monocapas de WSe2.
Se observó una división de energía superior a 10 meV entre las transiciones de excitón del valle K y K'.
Control óptico no resonante demostrado del grado de libertad del valle.

Conclusiones:

La manipulación coherente de la polarización del valle se puede lograr utilizando métodos ópticos ultrarrápidos.
El campo pseudomagnético generado en el valle abre nuevas vías para la valleytrónica.
Este enfoque es prometedor para el desarrollo de tecnologías de información cuántica.

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