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Low Temperature Magnetic Force Microscopy Study of Topological Insulators

Objetivo

"The study of topological insulators (TIs) is a budding field that is enjoying a fervor of activity. Recent discoveries show that new physics can exist in semiconductors with strong spin-orbit coupling. The most exotic class of TIs - ""strong topological insulators"" (STIs) - is a new state of matter, the hallmark of which is an odd number of topologically protected surface states. We will search for one of the most profound properties of these surfaces states. This predicted, but not yet observed property, is the topological magneto-electric effect (TME), which does not rely on interactions or many-body physics unlike most other emergent effects in solids. In the TME, an applied electric field induces a magnetic field that is proportional to an odd multiple of the fine structure constant. The TME arises when magnetism on the surface of the sample lifts the topological protection of the surface states by locally breaking time reversal symmetry. This gives rise to a special quantum Hall state. The TME is a fingerprint of that state. It is crucial to determine under what conditions the TME occurs, and whether other effects such as electron-electron interactions interfere with it. A low temperature magnetic force microscope (MFM) is an ideal tool for this project since it allows us to induce and measure both electric and magnetic fields at low temperatures. Guided by a suggestion by Qi et al. [Science 323, 1184 (2009)], we will subject the surface states to a magnetic field for breaking their time reversal invariance. This will give rise to the TME. Subsequently we will determine the magnetic field that is induced by electric charge near the surface of the sample by measuring the forces acting on the magnetic MFM tip. We will probe the TME by studying how it is affected by various parameters, such as temperature and applied magnetic field. Beyond establishing a profound property of the surface states, this will open the road to constructing exotic devices based on STIs."

Convocatoria de propuestas

FP7-PEOPLE-2010-RG
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Coordinador

TECHNION - ISRAEL INSTITUTE OF TECHNOLOGY
Aportación de la UE
€ 100 000,00
Dirección
SENATE BUILDING TECHNION CITY
32000 Haifa
Israel

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Tipo de actividad
Higher or Secondary Education Establishments
Contacto administrativo
Mark Davison (Mr.)
Enlaces
Coste total
Sin datos