Analytical Modeling of Electricity-Generating Two-Dimensional Electron Gases at LAO/STO/LTO Interfaces Using Coupled Schrödinger–Poisson Equations

Two-dimensional electron gases (2DEGs) in complex oxide heterostructures provide a powerful platform for enabling nanoscale energy-conversion mechanisms. In this work, we investigate LaAlO₃/SrTiO₃/LaTiO₃ (LAO/STO/LTO) interfaces as an engi-neered architecture for electricity generation, exploiting the combined effects of LAO-induced polar discontinuity, STO’s high-κ dielectric response, and LTO-driven electronic reconstruction. This trilayer system generates a strongly confined interfacial 2DEG with sheet densities in the 1013–1014 cm−2 range, enabling strong interaction with external electromagnetic fields and efficient charge displacement. To quantitatively capture the physics governing 2DEG formation and energy extraction, we develop a self-consistent analytical model solving the Schrödinger–Poisson equations. The SP module resolves quantum confinement, band bending, and carrier distribution at the LAO/STO/LTO interface, while the analytical engine models electromagnetic excitation (sheet charge density ns), field enhancement, and dynamic charge response across the heterostructure. This approach enables simultaneous evaluation of subband structure, interfacial potential, plasma-resonance behavior, and field-induced current genera-tion. Simulation results demonstrate that the asymmetric LAO/STO/LTO stack pro-duces a deep quantum well on the STO side, promoting strong 2DEG confinement and enhanced sensitivity to THz–IR excitation; under illumination the 2DEG exhibits res-onant carrier modulation, enhanced drift displacement, and energy-transfer pathways conducive to electricity generation. We additionally incorporate temperature depend-ence into the model and find monotonic increases in sheet charge density and conduc-tivity with temperature (measured at zero bias for 10 nm films), with LTO showing metallic-like, strongly temperature-dependent transport, STO exhibiting modest ther-mally activated behavior, and LAO remaining effectively insulating but most sensitive in relative terms—effects that alter subband occupancy, screening, and resonance con-ditions. The model clarifies how layer thickness, dielectric contrast, interface polariza-tion, and temperature jointly govern energy-conversion efficiency. Overall, the vali-dated Schrödinger–Poisson framework provides a predictive tool for optimizing oxide 2DEG power-generating structures and positions LAO/STO/LTO heterointerfaces as promising candidates for tunable, nanoscale energy-harvesting devices.