ABSTRACT
Graphene is the rst material of a truly two-dimensional (2D) crystal that was extracted from three-dimensional (3D) graphite using a simple technique, called micromechanical cleavage, in 2004.1,2 After ne-tuning, this technique now provides high-quality graphene crystallites of enough size for most research purposes. Before this, it was commonly believed that strictly 2D crystals were thermodynamically unstable and could not exist in the free state.3 Besides serving as a basic 2D model system for material science and condensed matter physics interest, it is the unique electronic properties including the ultra-high mobility,4 ballistic transport,5 the thinness and stability, quantum Hall effect (QHE), and so on that inspire the graphene upsurge which aims to make it promising for next generation nanoscale electronic and magnetic applications in real devices.6
