Uniaxial Strain Control of Bernal Bilayer Graphene

Bernal-stacked bilayer graphene has recently been found to exhibit spin-triplet superconductivity and an array of symmetry-broken states at zero magnetic field. These phases emerge at low carrier concentration in a perpendicular displacement field owing to the large density of states at van Hove singularities near the band extrema. Here, we develop a new experimental technique to apply in-plane uniaxial strain to bilayer graphene. We use a custom-built strain apparatus assembled from three piezo-stacks arranged in parallel, allowing us to exert continuous compressive or tensile strain at cryogenic temperatures. The application of strain is expected to deform the bilayer graphene band structure, potentially enabling a new means of studying and controlling its emergent correlated states. We will discuss ongoing efforts to measure transport in bilayer graphene as a function of strain both at zero field and in the quantum Hall regime.