Record-Breaking Magnetoresistance at the Edge of a Microflake of Natural Graphite

TL;DR

This study reports record-high magnetoresistance in natural graphite edges, reaching 10^7% at low temperatures and high magnetic fields, attributed to highly conducting 2D interfaces within the material.

Contribution

It demonstrates unprecedented magnetoresistance values in natural graphite, highlighting the role of internal 2D interfaces in enhancing magnetic response.

Findings

Magnetoresistance reaches ~10^7% at 21T and low temperatures.

Large MR values surpass previous reports for graphite and are comparable to Weyl semimetals.

Highly conducting 2D interfaces are responsible for the large MR.

Abstract

Placing several electrodes at the edge of a micrometer-size Sri Lankan natural graphite sample at distances comparable to the size of the internal crystalline regions, we found record values for the change of the resistance with magnetic field. At low temperatures and at $B \sim 21$T the magnetoresistance (MR) reaches $\sim 10^7$%. The MR values exceed by far all earlier reported ones for graphite and they are comparable or even larger (at $T > 50$K) than the largest reported in solids including the Weyl semimetals. The origin of this large MR lies in the existence of highly conducting 2D interfaces aligned parallel to the graphene planes.