Descripción del proyecto
Más cerca del primer dispositivo aislante topológico práctico 3D
Los aislantes topológicos son estados exóticos de la materia que se comportan como un aislante en su interior, pero cuya superficie contiene estados conductores, lo que significa que los electrones solo se pueden mover por la superficie del material. El transporte de electrones en aislantes topológicos 3D está dominado por los portadores en masa que limitan su potencial para ser usados en aplicaciones y dispositivos espintrónicos modernos. El proyecto MATTER, financiado con fondos europeos, proporcionará un itinerario alternativo para evitar esta barrera aplicando un enfoque de diseño de nanopartículas basado en las primeras fases de la sinterización. El trabajo experimental se complementará con una caracterización espectroscópica de las propiedades de las nanopartículas, así como con un trabajo teórico sobre los modelos de transporte. El proyecto tiene por objeto verificar los primeros dispositivos prácticos de transporte cuántico macroscópico que utilizan las propiedades electrónicas de los estados de superficie.
Objetivo
Ever since the discovery of topological surface states in three-dimensional (3D) topological insulators (TI), this fascinating physics has thrilled scientists. While arguable the transport properties of 3D TIs are of utmost importance for potential applications, they are extremely difficult to characterize, yet utilize for devices. The reason is that transport in those materials is always dominated by bulk carriers. Within this proposed research project, I will overcome the problem of bulk carrier domination conceptually by a nanoparticle-based materials’ design of interrupted early stage sintering. By this interrupted early stage sintering approach, I compact 3D TI nanoparticles at mild temperature and low pressure. The obtained highly porous macroscopic sample features a carrier density of the surface states in the order of 1018 cm-3, hence in a comparable order of magnitude as the bulk carrier density. Further, the interruptedly sintered nanoparticles impose energetic barriers for the transport of bulk carriers (hopping transport), while the connected surfaces of the nanoparticles provide a 3D percolation path for surface carriers. Within the preliminary work, my group tuned interruptedly sintered nanoparticles into a transport regime completely dominated by the surface states.
Within this project, nanoparticle-based macroscopic 3D TI materials will be developed towards test structures for devices. Their properties will be tailored by the nanoparticle synthesis (Objective 1) and the materials processing of interrupted early stage sintering (Objective 2). This is complemented by an in-depth characterization of the transport as well as spectroscopic properties and data modelling (Objective 3). My group will use this know-how for the fabrication of test devices (Objective 4). This combination will provide the first macroscopic quantum transport devices that utilize the unique electronic properties of surface states, overcoming the problem of bulk carrier domination
Ámbito científico
Programa(s)
Régimen de financiación
ERC-COG - Consolidator GrantInstitución de acogida
45141 Essen
Alemania