Abstract
The growth of a hexagonal FeTe (α-FeTe) thin layer on three-dimensional topological insulator Bi(2)Te(3) has been systematically investigated by combining scanning tunneling microscopy/spectroscopy (STM/STS) with density-functional theory (DFT) calculations. Through post-annealing at 560 K after room-temperature deposition of Fe onto Bi(2)Te(3), α-FeTe has been fabricated with an atomic lattice constant of 4.0 ± 0.1 Å, which is much smaller than the 4.4 ± 0.1 Å of the Te-terminated Bi(2)Te(3) surface. The lattice mismatch and a sufficiently large FeTe-Bi(2)Te(3) distance give rise to a moiré pattern with a periodicity of 6.0 ± 0.1 nm, corresponding to a p(15 × 15) superlattice. On the other hand, an enhanced projected density of states (PDOS) is found at about -0.8 eV and +1.4 eV of α-FeTe/Bi(2)Te(3) in the tunneling spectra. These enhancements, as interpreted from the DFT calculation, arise from the contribution of the 3d out-of-plane orbitals in Fe. DFT calculations also reveal nonzero net magnetization and indicate ferromagnetic (FM) order in the system - contrasting the well-studied bicollinear antiferromagnetism in β-FeTe/Bi(2)Te(3). To summarize, our successful fabrication of α-FeTe/Bi(2)Te(3) provides a distinct platform from β-FeTe/Bi(2)Te(3), enabling an exploration of the interplay between magnetism and interface-induced superconductivity.