Hetero-strain Induced Giant Injection Current in Twisted Bilayer Graphene Heterostructures

The moiré superlattices that twisted bilayer graphene (TBG) host exhibits rich phenomenology owing to its geometrically non-trivial bands. Here we predict that stacking and strain-controlled Bloch band geometry gives rise to giant circular injection currents in TBG. The high sensitivity of electronic wavefunctions on details of local atomic configurations allow strain enabled injection currents which sensitively depend on the alignment of graphene layers with hBN in TBG-hBN heterostructures that break sublattice symmetry. We argue that the giant injection currents proceed from large and highly peaked interband Berry curvature dipole density, which captures the quantum geometry associated with interband transitions giving rise to these currents. Strikingly, pronounced responses are found in the THz regime, which can be tuned by chemical potential.