Theoretical investigation of interface atomic structure of graphene on NiFe alloy substrate

TL;DR

This paper uses density functional theory to compare atomic structures of graphene on NiFe alloy interfaces created by transfer and evaporation, revealing process-dependent surface compositions.

Contribution

It provides a theoretical analysis of how different fabrication processes influence the atomic structure and composition of graphene/NiFe alloy interfaces.

Findings

Ni-rich surfaces are preferable for bare substrates

Fe surfaces are stable when graphene is adsorbed

Surface composition depends on fabrication process

Abstract

Two processes have been proposed to fabricate graphene/NiFe alloy interfaces for tunneling magnetoresistance devices. One is the transfer of graphene and the other is the evaporation of alloys onto graphene. The formation energy of a NiFe alloy substrate and the adsorption energy of graphene on the NiFe alloy substrate are investigated by a density functional theory calculations to reveal the difference in the atomic structure of the interface between the two processes. It is found that Ni-rich surfaces are preferable for the bare substrate, whereas Fe surfaces are stable for the graphene adsorbed on the substrate. This result indicates that the composition ratio of the surface layer depends on the interface fabrication process.