Executive Summary : | The development of van der Waals heterostructures using 2D materials has brought a revolution in the field of Condensed Matter Physics. Unlike traditional growth techniques such as pulse layer deposition or Molecular beam epitaxy, 2D materials allow for the manipulation of electronic properties through the creation of a long wavelength moiré superlattice that reconstructs the energy dispersion of the material. This is achieved by stacking layers of 2D materials with a small relative twist angle. One example is the magic-angle twisted bilayer graphene (MATBG), where two graphene layers are twisted at a 1.1-degree angle to each other. This twist angle is referred to as the "magic angle," and close to this angle, twisted bilayer graphene exhibits a range of phenomena, including exotic superconductivity, correlated insulating phases, orbital ferromagnetism, symmetry-breaking states, and giant thermopower. However, controlling the gate-tunable superconductivity and correlated states in twisted bilayer graphene is challenging due to twist angle disorder, which refers to the slow variation in the twist angle over the device length. This makes it a daunting task to trace the origin of the correlated states and superconductivity in MATBLG. Moreover, the twist angle of the devices is fixed at the nano fabrication stage and can no longer be changed at any later stage. Thus, performing twist angle dependence study requires large number of devices with different twist angle. In addition, each of these devices will have different defect configuration, charge inhomogeneity, twist angle disorder, strain etc. All of these make it next to impossible to study twist angle physics. To address this challenge, we propose a novel setup where any 2D materials can be stacked at will on top of each other, with in-situ rotation while measuring the electrical transport properties of the 2D interface. This setup can also be used for pressure-dependent electrical transport measurements and momentum-resolved microscopy experiments. The in-situ control over the twist angle will allow for the exploration of correlated physics in a single device in different coupling regimes, varying from weak, intermediate to very strong. Furthermore, this setup offers an opportunity to study twist angles since both small and larger twist angles are expected to produce correlated phases and topological states. Moreover, the study of twist angles has just begun, and it is still in its nascent phase, providing ample opportunity to explore correlated phenomena in 2D materials beyond magic-angle graphene. Additionally, there are many 2D van der Waals materials with properties of semi-metal, metal, insulator, semiconductor, and superconductor that can be stacked in our twistronics setup, opening up significant opportunities for designing van der Waal heterostructures with exotic magnetic, electrical, and topological properties required for quantum technologies. |