Scaled tight-binding model for a two-dimensional electron gas at the (001) LaAlO3/SrTiO3 interface

Progress in the fabrication of nanoscale systems based on the two-dimensional electron gas (2DEG) at the interface between LaAlO3 and SrTiO3 (LAO/STO) has created increased demand for simulations of these nanostructures, which typically range in size from tens to hundreds of nanometers. Due to the low lattice constant of LAO/STO, approximately 0.39 nm, these calculations become extremely time-consuming. Here, we present a scaling procedure for the tight-binding approximation of the LAO/STO 2DEG, defined on a square lattice that can be several times larger than in the conventional approach. The scaled model is analyzed within the context of quantum transport simulations and electronic structure calculations. Our findings demonstrate that the scaled model closely aligns with the ordinary one up to a scaling factor of 8. The applicability of the scaled Hamiltonian for systems with interacting electrons is also discussed. These results pave the way for more efficient simulations of LAO/STO nanostructures with realistic sizes relevant to experimental applications.