Universal spin diffusion length in polycrystalline graphene

Abstract

Graphene grown by chemical vapor deposition (CVD) is the most promising material for industrial-scale applications based on graphene monolayers. It also holds promise for spintronics; despite being polycrystalline, spin transport in CVD graphene has been measured over lengths up to 30 $\mu$m, which is on par with the best measurements made in single-crystal graphene. These results suggest that grain boundaries (GBs) in CVD graphene, while impeding charge transport, may have little effect on spin transport. However, to date very little is known about the true impact of disordered networks of GBs on spin relaxation. Here, by using first-principles simulations, we derive an effective tight-binding model of graphene GBs in the presence of spin-orbit coupling (SOC), which we then use to evaluate spin transport in realistic morphologies of polycrystalline graphene. The spin diffusion length is found to be independent of the grain size, and is determined only by the strength of the substrate-induced SOC. This result is consistent with the D'yakonov-Perel' mechanism of spin relaxation in the diffusive regime, but we find that it also holds in the presence of quantum interference. These results clarify the role played by GBs and demonstrate that the average grain size does not dictate the upper limit for spin transport in CVD-grown graphene, a result of fundamental importance for optimizing large-scale graphene-based spintronic devices.

References in corpus (10)

• Graphene Spintronics
• Control and Characterization of Individual Grains and Grain Boundaries in Graphene Grown by Chemical Vapor Deposition
• Electronic transport in polycrystalline graphene
• Room-temperature ferromagnetism in graphite driven by 2D networks of point defects
• Mechanical properties of polycrystalline graphene based on a realistic atomistic model
• Spin Proximity Effects in Graphene/Topological Insulator Heterostructures
• Linear Scaling Quantum Transport Methodologies
• Heterostructures of graphene and hBN: electronic, spin-orbit, and spin relaxation properties from first principles
• Spin communication over 30 $\mu$m long channels of chemical vapor deposited graphene on SiO${}_2$
• Dyakonov-Perel spin relaxation near metal-insulator transition and in hopping transport

Cited by in corpus (10)

• Manipulation of Spin Transport in Graphene/Transition Metal Dichalcogenide Heterobilayers upon Twisting
• Thermal Transport in Amorphous Graphene with Varying Structural Quality
• Robust Spin Interconnect with Isotropic Spin Dynamics in Chemical Vapour Deposited Graphene Layers and Boundaries
• Electric fields and substrates dramatically accelerate spin relaxation in graphene
• Sublattice symmetry breaking and ultra low energy excitations in Graphene-on-hBN Heterostructures
• Structural dynamics of polycrystalline graphene
• Anomalous magnetic suppression of spin relaxation in a two-dimensional electron gas in a GaAs/AlGaAs quantum well
• Robust quantum engineering of current flow in carbon nanostructures at room temperature
• Upper limit of spin relaxation in suspended graphene
• Electron-hole asymmetry in electrical conductivity of low-fluorinated graphene: Numerical study