Twistronics

Twistronics

Subject: Science & Tech

Section: IT

Context- Graphene material has been known to show exotic phases ranging from insulator to superconductor.

Concept-

About Twistronics:

• Twistronics (from twist and electronics) is the study of how the angle (the twist) between layers of two-dimensional materials can change their electrical properties.
• Materials such as bilayer graphene have been shown to have vastly different electronic behavior, ranging from non-conductive to superconductive, that depends sensitively on the angle between the layers.

Twisted Bilayer Graphene:

• Graphene is a two dimensional material comprising a single layer of carbon atoms arranged in a hexagonal lattice.
• Stacks of graphene layers can make up graphite.
• Graphene possesses sev­eral interesting properties by itself, and, moreover, it can be combined with other materials to form useful dev­ices.
• One such material is twisted bilayer graphene.
• This is made by placing two layers of graphene on top of each other such that they are aligned well, and then twist­ing one layer, so that it makes a well calibrated, known angle with respect to the former.
• When such a twist is given, the lattice shows what are called moire patterns. Moire patterns are wavy fringe like patterns that we see, for example, when two layers of synthetic fabric overlap and move with res­pect to each other.
• Bilayer graphene can be used to construct field effect transistors or tunneling field effect transistors, exploiting the small energy gap.
• A material system known as magic-angle twisted trilayer graphene exhibits superconductivity. The observation that this superconductivity persists under a strong magnetic field could lead to advances in quantum computation.