Density functional study of twisted graphene L10-FePd heterogeneous interface

Graphene on L1(0)-FePd(001), which has been experimentally studied in recent years, is a heterogeneous interface with a significant lattice symmetry mismatch between the honeycomb structure of graphene and tetragonal alloy surface. In this work, we report on the density functional study of its atomic-scale configurations, electronic and magnetic properties, and adsorption mechanism, which have not been well understood in previous experimental studies. We propose various atomic-scale models, including simple nontwisted and low-strain twisted interfaces, and analyze their energetical stability by performing structural optimizations using the van der Waals interactions of both DFT-D2 and optB86b-vdW functionals. The binding energy of the most stable structure reached E-B = -0.22 eV/atom for DFT-D2 (E-B = -0.19 eV/atom for optB86b-vdW). The calculated FePd-graphene spacing distance was approximately 2 angstrom, which successfully reproduced the experimental value. We also find out characteristic behaviors: the modulation of pi-bands, the suppression of the site-dependence of adsorption energy, and the rise of moire-like corrugated buckling. In addition, our atomic structure is expected to help build low-cost computational models for investigating the physical properties of L1(0) alloys/two-dimensional interfaces. Published under an exclusive license by AIP Publishing.

Automated summary

In this study, density functional theory was used to investigate the atomic-scale configurations, electronic and magnetic properties, and adsorption mechanism of graphene on L1(0)-FePd(001). Various atomic-scale models were proposed and the energetical stability was analyzed. The study provides insights into the physical properties of the L1(0)-FePd(001) interface and facilitates the construction of low-cost computational models.