Formation mechanism of bound states in graphene point contacts

TL;DR

This paper investigates the formation of quasibound and bound states in narrow graphene point contacts, revealing how edge states and interface geometry influence electronic localization, with implications for graphene-based nanoelectronics.

Contribution

It introduces a theoretical framework for understanding quasibound and bound states in ultrashort graphene quantum point contacts, highlighting the role of edge states and interface modifications.

Findings

Long-lived quasibound states exist in ultrashort graphene QPCs.

Edge states are key to the formation of these states.

Bound states can be achieved with bearded sites.

Abstract

Electronic localization in narrow graphene constrictions is theoretically studied, and it is found that long-lived quasibound states (QBSs) can exist in a class of ultrashort graphene quantum point contacts (QPCs). These QBSs are shown to originate from the dispersionless edge states that are characteristic of the electronic structure of generically terminated graphene, in which pseudo-time-reversal symmetry is broken. The QBSs can be regarded as interface states confined between two graphene samples, and their properties can be modified by changing the sizes of the QPC and the interface geometry. In the presence of bearded sites, these QBSs can be converted into bound states. Experimental consequences and potential applications are discussed.