Graphene is an outstanding material with unique electronic, chemical and mechanical properties. In monolayer graphene, electrons behave like relativistic massless particles making it possible to observe relativistic effects like perfect transmission through a potential barrier (Klein tunneling) and a modified quantum Hall effect. At the same time, graphene is extremely strong, flexible and chemically inert.
In this project the interplay between mechanical deformation of graphene membranes and electronic properties will be investigated. Of particular interest is the creation of artificial gauge fields due to strain engineering and the interaction with an external magnetic field.
Interestingly, a gauge field can be created just by introducing non-uniform strain into a graphene membrane. Since mechanical deformation of a graphene membrane does not break time reversal symmetry, the gauge field does not have exactly the same effect on electrons as an externally applied magnetic field. Instead, the gauge field has opposite sign for electrons of different valleys of the electronic band structure.
We will develop graphene membranes with tunable homogenous gauge fields by strain engineering. Several techniques will be employed to measure and characterize intrinsic strain. Focus of the research will be the investigation of strained graphene membranes in the quantum Hall regime. A detailed understanding of strained graphene constitutes also one step towards all-graphene integrated circuits and is a possible approach to 'valleytronics'.