Unusual electronic properties of clean and disordered zigzag graphene nanoribbons

by Yshai Avishai

at Condensed Matter Theory Seminar

Wed, 13 Jun 2018, 13:30
Physics building (#54) room 207


We revisit the problem of electron transport in clean and disordered zigzag graphene nanoribbons and expose numerous hitherto unknown peculiar properties of these systems at zero energy where both sublattices decouple because of chiral symmetry For clean ribbons we give a quantitative description of the unusual power law dispersion of the central energy bands and of its main consequences including the strong divergence of the density of states near zero energy and the vanishing of the transverse localization length of the corresponding edge states In the presence of off diagonal disorder which respects the lattice chiral symmetry all zero energy localization properties are found to be anomalous Recasting the problem in terms of coupled Brownian motions enables us to derive numerous asymptotic results by analytical means From the mere viewpoint of the transfer matrix formalism zigzag ribbons provide a case study with many unusual features The transfer matrix describing propagation through one unit cell of a clean ribbon is not diagonalizable at zero energy In the disordered case we encounter non trivial random matrix products such that all Lyapunov exponents vanish identically

Created on 08-06-2018 by Bar Lev, Yevgeny (ybarlev)
Updaded on 08-06-2018 by Bar Lev, Yevgeny (ybarlev)