title: Extraordinary magnetoresistance in graphite: experimental evidence for the time-reversal symmetry breaking.
abstract: We report a highly anisotropic in-plane magnetoresistance (MR) in graphite that possesses in-plane parallel line-like structural defects. In a current direction perpendicular to the line defects (LD), MR is negative and linear in low fields with a crossover to a positive MR at higher fields, while in a current direction parallel to LD, we observed a giant super-linear positive MR. These extraordinary MRs are respectively explained by a hopping magnetoresistance via non-zero angular momentum orbitals, and by the magnetoresistance of inhomogeneous media. The linear negative orbital MR is a unique signature of the broken time-reversal symmetry (TRS). We discuss the origin of the disorder-induced TRS-breaking in graphite.
authors.affiliation: Instituto de Fisica 'Gleb Wataghin', Universidade Estadual de Campinas, UNICAMP 13083-970, Campinas, São Paulo, Brazil.
authors.forename: Y
authors.initials: Y
authors.lastname: Kopelevich
authors.forename: R R
authors.initials: RR
authors.lastname: da Silva
authors.forename: B C
authors.initials: BC
authors.lastname: Camargo
authors.forename: A S
authors.initials: AS
authors.lastname: Alexandrov