Roller-Coaster in a Flatland: Magnetoresistivity in Eu-intercalated Graphite

TL;DR

This paper provides a microscopic explanation for the roller-coaster-like magnetoresistivity observed in Eu-intercalated graphite, highlighting the role of spin excitations and their evolution under magnetic fields in a novel 2D material system.

Contribution

It offers the first detailed microscopic analysis of the magnetoresistivity behavior in EuC$_6$, linking it to spin excitations in Eu-planes and demonstrating the potential of synthetic 2D materials for studying exotic spin phenomena.

Findings

Resistivity dominated by Eu-plane spin excitations

Nontrivial evolution of spin excitations with magnetic field

Powerful insights into exotic spin behaviors in 2D materials

Abstract

Novel phenomena in magnetically-intercalated graphite has been a subject of much research, pioneered and promoted by M.~S. and G.~Dresselhaus and many others in the 1980s. Among the most enigmatic findings of that era was a dramatic, roller-coaster-like behavior of the magnetoresistivity in EuC$_6$ compound, in which magnetic Eu$^{2+}$ ions form a triangular lattice that is commensurate to graphite honeycomb planes. In this study, we provide a long-awaited {\it microscopic} explanation of this behavior, demonstrating that the resistivity of EuC$_6$ is dominated by spin excitations in Eu-planes and their highly nontrivial evolution with the magnetic field. Together with our theoretical analysis, the present study showcases the power of the synthetic 2D materials as a source of potentially significant insights into the nature of exotic spin excitations.