Dimensional crossover of quantum Hall conductivity in graphite through proton-irradiation

In this study, quantum Hall effect-like plateaus, exhibiting the behavior of single- and multi-graphene, are observed in ZYA-grade highly oriented pyrolytic graphite (HOPG). Massless Dirac carriers and massive normal carriers of the HOPG are distinguished from the analysis of Shubnikov-de Haas and de Haas van Alphen oscillations. The quantum Hall effect-like plateaus are diminished after proton-irradiation owing to increasing interlayer interaction along the c-axis that causes the change of two-dimensional massless carriers of the HOPG to three-dimensional massive carriers. Moreover, tight-binding calculations exhibit similar diminishing plateaus of the Hall conductivity of HOPG as the interlayer interaction increases. This observation of dimensional crossover of the Hall conductivity demonstrates that proton-irradiation would be a useful tool to control quantum transport in HOPG through manipulating its interlayer interaction.