Topological effects of three-dimensional porous graphene on Dirac quasiparticles

TL;DR

This study explores how the topological structure of 3D porous graphene influences Dirac quasiparticles' electrical behavior, revealing that intrinsic curvature and pore size significantly affect quantum transport phenomena.

Contribution

It demonstrates that the topological defects and curvature in 3D porous graphene induce intervalley scattering, breaking chirality and altering electrical properties, which is a novel insight into topological effects in graphene.

Findings

Small pores lead to weak localization at low temperatures.

Intrinsic curvature increases intervalley scattering and chirality mixing.

Topological defects are linked to changes in electronic scattering processes.

Abstract

This paper reports on the topological effects of three-dimensional (3D) porous graphene with tunable pore sizes and a preserved 2D graphene system of Dirac quasiparticles on its electrical properties. This 3D architecture is characterized by the intrinsic curvature of smoothly interconcnected graphene sheets without edges, the structures and properties of which can be controlled with its pore sizes. The impact of pore size on the electrical transport properties was investigated through magnetoresistance measurements. We observed that 3D graphene with small pores exhibits transitioning to weak localization with decreasing temperature. The comparison with the theory based on the quantum correction clarified that an increase in the intrinsic curvature significantly induces the intervalley scattering event, which breaks the chirality. This increase in the intervalley scattering rate originates from the unique topological effects of 3D graphene, i.e., the topological defects required to form the high curvature and the resulting chirality mixing. We also discuss the scattering processes due to microscopic chemical bonding states as found by high spatial-resolved X-ray photoemission spectral imaging, to support the validity of our finding.