ARPES tagged posts

Evidence of a new phenomenon: Quantum tornadoes in momentum space

Quantum tornado in momentum space: In the quantum material tantalum arsenide (TaAs), electrons form vortices in momentum space. Momentum space is a physics concept used to analyze how electrons behave in solids. A research team from the Cluster of Excellence ct.qmat at Würzburg and Dresden has now provided the first experimental evidence of these quantum tornadoes. (Image: think-design | Jochen Thamm)

A team of researchers from Würzburg has for the first time experimentally demonstrated a quantum tornado. Electrons form vortices in the momentum space of the quantum semi-metal tantalum arsenide.

Scientists have long known that electrons can form vortices in quantum materials...

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Graphene on the way to Superconductivity

The bandstructure in a double layer of graphene was scanned by ARPES at synchrotron light source BESSY II. Credit: HZB

The bandstructure in a double layer of graphene was scanned by ARPES at synchrotron light source BESSY II.
Credit: HZB

Scientists have found evidence that double layers of graphene have a property that may let them conduct current completely without resistance. They probed the band structure at BESSY II with extremely high resolution ARPES and could identify a flat area at a surprising location.

In April 2018, a group at MIT, USA, showed that it is possible to generate a form of superconductivity in a system of two layers of graphene under very specific conditions: To do this, the two hexagonal nets must be twisted against each other by exactly the magic angle of 1.1°. Under this condition a flat band forms in the electronic structure...

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