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

Novel phenomena in magnetically-intercalated graphite has been a subject of much research in the 1980s, with the most enigmatic findings of that era being a dramatic, roller-coaster-like behavior of the magnetoresistivity in EuC₆ compound, which remained unexplained until now. In our recent study, we have provided a long-awaited microscopic explanation of this behavior, demonstrating that the resistivity of EuC₆, in which magnetic Eu²⁺ ions form a triangular lattice that is commensurate with the graphite honeycomb planes, is dominated by spin excitations in Eu-planes and their highly nontrivial evolution with the magnetic field. Together with our theoretical analysis, this study showcases the power of the synthetic 2D materials as a potential source of significant novel insights into the nature of exotic spin excitations such as fractionalized spinons in a quantum spin liquid.