# Large Positive Magnetoconductance in Carbon Nanoscrolls

## TL;DR

Carbon nanoscrolls show a large increase in electrical conductivity when exposed to strong magnetic fields, even with imperfections.

## Contribution

The study reveals that carbon nanoscrolls exhibit large positive magnetoconductance due to zero-energy modes induced by magnetic fields.

## Key findings

- Ballistic conductance increases by about 200% under axial magnetic fields of several Tesla.
- Positive magnetoconductance is preserved and even enhanced in imperfect nanoscrolls with disorder.
- Magnetic-field-induced zero-energy modes are responsible for the observed magnetoconductance.

## Abstract

We theoretically demonstrate that carbon nanoscrolls,
spirally
wrapped graphene layers with open end points, can be characterized
by a large positive magnetoconductance. We show that when a carbon
nanoscroll is subject to an axial magnetic field of several Tesla,
the ballistic conductance at low carrier densities of the nanoscroll
increases by about 200%. Importantly, we find that this positive magnetoconductance
is not only preserved in an imperfect nanoscroll (with disorder or
mild interturn misalignment) but can even be enhanced in the presence
of on-site disorder. We prove that the positive magnetoconductance
comes about with the emergence of magnetic-field-induced zero-energy
modes, specific to rolled-up geometries. Our results establish curved
graphene systems as a new material platform displaying sizable magnetoresistive
phenomena.