Field and temperature dependence of intrinsic diamagnetism in graphene: Theory and experiment

Intrinsic diamagnetism of graphene is studied both theoretically and experimentally, to unravel the magnetic response of chiral massless fermions. Comprehensive formulas predicting the variation of graphene magnetization with magnetic field and temperature are developed. Graphene magnetization M at low temperatures is particularly large and M [is proportional to] -[radical]B, intrinsically different from normal materials. The quantum Berry phase of [pi] and linear energy dispersion are responsible for this intriguing macroscopic behavior. The temperature dependence of magnetization is successfully formulated by a Langevin-like function. The de Haas-van Alphen oscillations are predicted in the case of doping. Correspondingly, experiments at different temperatures are conducted on highly pure, mass-produced graphene flakes derived from SiC single crystals, which exhibit very strong diamagnetism. The measured results agree well with the theoretical ones in both magnitude and trend.