First Principles Study of Electronic Structure and Transport in Graphene Grain Boundaries

Abstract

Grain boundaries play a major role for electron transport in graphene sheets grown by chemical vapor deposition. Here we investigate the electronic structure and transport properties of idealized graphene grain boundaries (GBs) in bi-crystals using first principles density functional theory (DFT) and non-equilibrium Greens functions (NEGF). We generated 150 different grain boundaries using an automated workflow where their geometry is relaxed with DFT. We find that the GBs generally show a quasi-1D bandstructure along the GB. We group the GBs in four classes based on their conductive properties: transparent, opaque, insulating, and spin-polarizing and show how this is related to angular mismatch, quantum mechanical interference, and out-of-plane buckling. Especially, we find that spin-polarization in the GB correlates with out-of-plane buckling. We further investigate the characteristics of these classes in simulated scanning tunnelling spectroscopy and diffusive transport along the GB which demonstrate how current can be guided along the GB.

References in corpus (12)

• Boron nitride substrates for high-quality graphene electronics
• Electronic transport in polycrystalline graphene
• SIESTA: recent developments and applications
• Scanning Tunneling Spectroscopy of Graphene on Graphite
• Improvements on non-equilibrium and transport Green function techniques: the next-generation transiesta
• Mechanical properties of polycrystalline graphene based on a realistic atomistic model
• Grain Boundary Loops in Graphene
• Electronic States of Graphene Grain Boundaries
• Linear and nonlinear optical response of crystals using length and velocity gauges: Effect of basis truncation
• First-Principles Electron Transport with Phonon Coupling: Large-Scale at Low Cost
• Grain Boundaries in Graphene on SiC(000$\bar{1}$) Substrate
• Quantum Hall effect in polycrystalline graphene: The role of grain boundaries