First-Principles Investigation of Superconducting Proximity Effects in a Bi₂Te₃/FeTe Heterostructure

Hybrid structures combining the high-critical-temperature superconductor Fe(Te,Se) with the three-dimensional topological insulator Bi₂Te₃ have recently been synthesized, providing promising platforms for realizing Majorana-bound states and advancing topological quantum devices. In this work, we investigate the microscopic mechanisms governing the superconducting proximity effect in FeTe/Bi₂Te₃ heterostructures using first-principles calculations. By analyzing the orbital-resolved band structure, we find that interlayer hybridization is not dominated by nearest-neighbor Te–Te coupling, but instead arises from strong interactions between Fe d orbitals and Te p orbitals. This behavior reflects the pronounced screening effects of the Fe layer and agrees with recent experimental findings. Based on our first-principles results, we further construct a minimal tight-binding Hamiltonian to quantify the tunneling strength across the interface.