Long-range order of polygonal grain boundaries

N. Sarkar, P. R. Bandaru, R. C. Dynes

Research output: Contribution to journalArticlepeer-review

Abstract

Atomic-scale spatial resolution was achieved in the mapping and spectroscopy of polygonal grain boundaries (GBs) on atomically flat highly oriented pyrolytic graphite using scanning tunneling microscopy (STM). These GBs are long-range ordered one-dimensional periodic structures comprising pentagon-heptagon pairs. A comprehensive study combining local electronic, valleytronic, mechanical, and topological properties is conducted on this GB which reveals the interplay between these properties. On the atoms and bonds of individual GB polygons, spatially localized conductance states were probed, in addition to edge states. The spatial extent of these states was observed on GB by bias-dependent imaging. The electron scattering angle at the GB edges was also modulated with a sample bias which exhibited valley flipping and unique quantum interference effects such as backscattering and intervalley scattering. In situ strain-induced mechanical and electronic modifications were observed through surface deformation caused by the STM tip, revealing flattened electronic energy band dispersion and shifts in carrier doping.

Original languageEnglish
Article number045103
JournalPhysical Review B
Volume111
Issue number4
DOIs
StatePublished - Jan 15 2025
Externally publishedYes

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