2009/08/10 by S. Krompiewski
Materials Science · Mathematics · Physics and Astronomy · #Carbon Nanotubes in Composites #Condensed matter physics #Conductance #Conductivity #Electrical resistivity and conductivity #Electronic structure #Enhanced Data Rates for GSM Evolution #Fano factor #Ferromagnetism #Geometry #Giant magnetoresistance #Graphene #Graphene nanoribbons #Graphene research and applications #Magnetic field #Magnetoresistance #Materials science #Mathematics #Nanotechnology #Optics #Physics #Quantum and electron transport phenomena #Quantum mechanics #Shot noise #Spin (aerodynamics) #Tight binding #Zigzag #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.80.075433
to appear in PRB
arxiv created 2009/08/10 · openalex publication_date 2009/08/28 · arxiv updated 2015/05/13 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Based on a tight-binding model and a recursive Green's function technique, spin-dependent ballistic transport through tiny graphene sheets (flakes) is studied. The main interest is focused on electrical conductivity, giant magnetoresistance (GMR), and shot noise. It is shown that when graphene flakes are sandwiched between two ferromagnetic electrodes, the resulting GMR coefficient may be quite significant. This statement holds true both for zigzag and armchair chiralities, as well as for different aspect (width/length) ratios. Remarkably, in absolute values the GMR of the armchair-edge graphene flakes is systematically greater than that corresponding to the zigzag-edge graphene flakes. This finding is attributed to the different degree of conduction channel mixing for the two chiralities in question. It is also shown that for big aspect ratio flakes, three-dimensional end-contacted leads, very much like invasive contacts, result in nonuniversal behavior of both conductivity and Fano factor.