Dirac semimetal phases in chiral carbon nanoscrolls

TL;DR

This paper explores how chirality in carbon nanoscrolls influences their electronic topological properties, revealing the emergence and protection of Dirac cones under magnetic fields.

Contribution

It provides a theoretical analysis of topological Dirac cones in chiral carbon nanoscrolls, highlighting the effects of chirality and magnetic fields on their electronic structure.

Findings

Dirac cones appear at non-half flux quantum values in chiral nanoscrolls.

Dirac cones are topologically protected by combined inversion-time reversal symmetry.

Number and distribution of Dirac cones depend on turns and magnetic field strength.

Abstract

Chirality induced by rolling a two-dimensional material into a spiral geometry reshapes its electronic band structure. In this work, we theoretically investigate the topological properties of carbon nanoscrolls under an axial magnetic field, focusing on structures in which chirality is encoded through shifted edge alignments. In contrast to unshifted structures, where mirror symmetry pins the Dirac cones to half a flux quantum, chiral carbon nanoscrolls lack this symmetry, and Dirac cones emerge at magnetic flux values away from half a flux quantum. We demonstrate that these Dirac cones are topologically protected by combined inversion-time reversal symmetry and remain robust even when sublattice symmetry is broken. Furthermore, we show that the number of Dirac cones and their real-space probability distributions depend on the number of turns and the magnetic field strength. Our study elucidates the role of chirality in the band topology of nanoscroll geometries.