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El transporte de espín electrónico y la precesión de espín en capas simples de grafeno a temperatura ambiente
Nikolaos Tombros1, Csaba Jozsa, Mihaita Popinciuc
1Physics of Nanodevices, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Nature
|July 17, 2007
Resumen
Los investigadores observaron el transporte de espín y la precesión de espín de Larmor a distancias de micrómetros en capas de grafeno individuales. Esto demuestra el grafeno.
Área de la Ciencia:
- Física de la materia condensada Física de la materia condensada
- Ciencia de los materiales Ciencia de los materiales.
- Spintronics es una empresa de Spintronics.
Sus antecedentes:
- La estructura única de banda electrónica del grafeno permite nuevos fenómenos de transporte.
- La baja órbita de espín y las interacciones hiperfinas del grafeno lo hacen prometedor para la espintrónica.
- Estudios previos observaron varios fenómenos de transporte electrónico en el grafeno.
Objetivo del estudio:
- Para investigar el transporte de espín y la precesión de espín de Larmor en capas de grafeno único.
- Evaluar el potencial del grafeno para aplicaciones espintrónicas.
- Para determinar la longitud de coherencia de espín y la polarización de espín de contacto en el grafeno.
Principales métodos:
- Utilizó una geometría de válvula de giro no local con contactos de cuatro terminales.
- Empleó electrodos de cobalto ferromagnéticos en contacto con capas de grafeno individuales a través de una fina capa de óxido.
- Se midieron señales de giro a varias temperaturas (4,2 K, 77 K y temperatura ambiente).
Principales resultados:
- Se observaron claras señales de espín bipolar que reflejan la magnetización de los electrodos, lo que indica una coherencia de espín extendida.
- Se ha demostrado el transporte de espín y la precesión de Larmor en distancias de micrómetros.
- Se extrajo una longitud de relajación de giro de 1.52 μm a temperatura ambiente, con una dependencia mínima de la temperatura.
- Se calcula que la polarización de espín de contacto ferromagnético es de aproximadamente el 10%.
Conclusiones:
- Las capas individuales de grafeno apoyan el transporte de espín a distancias de micrómetros.
- El grafeno es un material viable para dispositivos espintrónicos debido a sus largas longitudes de coherencia de espín.
- Los fenómenos observados son robustos a través de un rango de temperaturas.
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