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Luke Soneji

Publications and source records attributed to Luke Soneji.

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

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.

cond-mat.mes-hall

Rhombohedral graphite junctions as a platform for continuous tuning between topologically trivial and non-trivial electronic phases

Manipulating the topological properties of quantum states can provide a way to protect them against disorder. However, typically, changing the topology of electronic states in a crystalline material is challenging because their nature is underpinned by chemical composition and lattice symmetry that are difficult to modify. We propose junctions between rhombohedral graphite crystals as a platform that enables smooth transition between topologically trivial and non-trivial regimes distinguished by the absence or presence of topological junction states. By invoking an analogy with the Su-Schrieffer-Heeger model, the appearance of topological states is related to the symmetry of the atomic stacking at the interface between the crystals. The possibility to explore both the topological and non-topological phases is provided by sliding the crystals with respect to each other.

cond-mat.mes-hall