Seminar at the Accelerator – P. Esquinazi (Leipzig Uni.)
Title: High-field and high-temperature magnetoresistance reveals the superconducting behavior of the stacking faults in graphite.
Abstract: In spite of 40 years of experimental studies and several theoretical proposals, an overall interpretation of the complex behavior of the magnetoresistance (MR) of multilayer graphene, i.e. graphite, at high fields (𝐵 ≲ 70 T) and in a broad temperature range is still lacking. Part of the complexity is due to the contribution of stacking faults (SFs), which most of thick enough multilayer graphene samples have. We propose a procedure that allows us to extract the SF contribution to the MR we have measured at 0.48 K ≤ 𝑇 ≤ 250 K and 0 T ≤ 𝐵 ≲ 65 T. We found that the MR behavior of part of the SFs is similar to that of granular superconductors with a superconducting critical temperature 𝑇𝑐 ∼ 350 K, in agreement with recent publications. The measurements were done on a multilayer graphene TEM lamella, contacting the edges of the two-dimensional SFs.