Physics at van der Waals interfaces: Twists, incommensurability and emergent phenomena

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• Marcin Mucha-Kruczynski (Bath)
• Thursday 30 January 2020, 13:15-14:45
• Theory Library.

If you have a question about this talk, please contact Dr Hannah Price.

Note the new time for Theory seminars this term

Since the isolation of graphene in 2004, many other atomically thin crystals have been produced. Moreover, they are now being stacked on top of each other to form so called van der Waals heterostructures – new artificial materials assembled layer by atomic layer. In my talk, I will discuss some of the physical phenomena observed in such structures, mainly emerging due to the interaction between two different crystals and/or driven by changes in the geometry at an interface between van der Waals-coupled materials. I will start by looking at the importance of layer stacking order and show how we can distinguish between Bernal and rhombohedral stackings in graphite films. I will then present ReSe2 as a case study of how the number of layers in a crystal of semiconducting transition metal dichalcogenides influences its electronic band structure. After that, I will move to “twisted” heterostructures in which two consecutive layers are placed at an angle between their crystallographic directions. Using twisted bilayer graphene as an example, I will address the question of periodicity in such twisted bilayers as well as how we can extract information about the interlayer coupling. I will close by looking at twist-induced effects in graphene on hexagonal boron nitride: appearance of secondary Dirac points the electronic spectrum and so called Hofstadter’s butterfly in the presence of a strong perpendicular magnetic field. Finally, I will show that competition between intra- and interlayer interactions can also lead to coupling between electrons and the lattice.

This talk is part of the Theoretical Physics Seminars series.

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• Bham Talks
• Theoretical Physics Seminars
• Theory Library
• What's on in Physics?

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