Electron localization, charge redistribution, and emergence of topological states at graphite junctions

TL;DR

This study investigates how stacking arrangements in graphite influence electronic states, revealing that junctions often host localized states, with flat bands indicating potential for correlated electronic phenomena.

Contribution

It demonstrates the widespread presence of junction-localized states in graphite and uncovers flat-band states in various stacking configurations, expanding understanding of topological and correlated states.

Findings

Junction-localized electronic states are common in graphite.

Most systems with rhombohedral stacking support flat bands.

Flat-band states extend into Bernal systems with finite rhombohedral regions.

Abstract

Low-energy electronic behavior in graphite crystals is highly dependent on the relative stacking arrangement of the constituent layers. Topologically non-trivial electronic states can arise due to interrupted rhombohedral (ABC) stacking, localized at the edges of the stacking region, but not in the case of Bernal (AB) stacking. Here, we study the electronic properties of junctions between half-crystals of graphite of either Bernal or rhombohedral stacking, using a charge self-consistent tight-binding method and embedding potentials to account for the influence of layers far from the junction. We find junction-localized electronic states to be a ubiquitous feature, and all systems but one involving a rhombohedral half-crystal support a flat-band expected to exhibit electronic instabilities and strongly-correlated states. Nascent flat-band states associated with finite rhombohedral stacking sequences extend the physics into pure Bernal systems.