Ari Harju: Dominant source of disorder in graphene: Charged impurities or ripples?

posted 1 Jun 2016, 06:40 by info admin
Ari Harju, Andreas Uppstu, and Zheyong Fan, Department of Applied Physics, Aalto University, Finland

Experimentally produced graphene sheets exhibit a wide range of mobility values. Both extrinsic charged impurities and intrinsic ripples (corrugations) have been suggested to induce long-range disorder in graphene and could be a candidate for the dominant source of disorder. Here, using large-scale molecular dynamics and quantum transport simulations, we find that the hopping disorder and the gauge and scalar potentials induced by the ripples are short-ranged, in strong contrast with predictions by continuous models, and the transport fingerprints of the ripple disorder are very different from those of charged impurities. We conclude that charged impurities are the dominant source of disorder in most graphene samples, whereas scattering by ripples is mainly relevant in the high carrier density limit of ultraclean graphene samples (with a charged impurity concentration < 10 ppm) at room and higher temperatures., submitted to Physical Review Letters

Ari Harju leads a Quantum many-body physics group at Department of Applied Physics, Aalto University, Helsinki, Finland. The group is part of an Academy of Finland Center of Excellence. He has authored 100+ international peer-reviewed journal articles, including high-rank journals like Nature Physics.