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Student colloquium Department of Physics Public / media Students

Student colloquium - Kasper Rønning Pedersen: Twistronics - a new twist on quantum materials

Info about event

Time

Thursday 29 April 2021,  at 14:15 - 15:00
[Translate to English:] Twisted bilayer graphene, assembled from two layers of graphene with a relative twist.
[Translate to English:] Twisted bilayer graphene, assembled from two layers of graphene with a relative twist.

Supervisor: Philip Hofmann

Two-dimensional material physics saw its light after the first synthetization of graphene in 2004. In contrast to bulk materials, such two-dimensional sheets can be stacked on top of each other to form new artificial materials in the form of so-called superlattices. By twisting the sheets relative to each other, it turns out that one can change the properties of the superlattice drastically. This observation is the key point in twistronics, where one studies how the properties of the superlattice are changed by the twist-angle.

The most famous example is twisted bilayer graphene, composed of two layers of graphene with a relative twist (see figure). Other examples are superlattices composed of transition metal dichalcogenides, a class of materials closely related to graphene.

In this colloquium, I will outline the development of twistronics. Furthermore, I will discuss twisted bilayer graphene and give a comparison to single layer graphene. Finally, I will consider a superlattice made of two-dimensional MoSe2 and WSe2 sheets, where twist-angle dependent electron-hole bound states have been realized.