Quantum Transport in Disordered Graphene: Scaling Properties, Magnetism and Spin relaxation Mechanism

CIC nanoGUNE Seminars

Stephan Roche, Catalan Institute of Nanotechnology
nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
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Quantum Transport in Disordered Graphene: Scaling Properties, Magnetism and Spin relaxation Mechanism Host: Emilio Artacho > This talk will focus on the presentation of transport properties in > graphene-based-materials containing disorder or specific structural > morphologies such as grain boundaries in polycrystalline samples. The used > multiscale quantum transport methodologies combine state-of-the-art first- > principles with real space order N tight-binding approaches, will be shown > to enable in-depth analysis of charge (and spin) transport fingerprints of > realistic models of defected graphene of interest for industrial > applications. > > > > Here, we will explore the effect of grain boundaries in polycrystalline > graphene limiting charge mobilities in large-scale materials used in > transparent electrodes applications. We will also discuss the origin of spin > relaxation in graphene which is currently a highly debated issue, with > reported spin diffusion times about 1 nanosecond, that is three orders of > magnitude lower than expected, whereas the nature of relaxation fluctuates > between Elliot-Yaffet and Dyakonov Perel mechanism with no consensus and > puzzling experimental features. All these issues also point towards > revisiting the way such fundamental length scales are usually extracted in > experiments (Hanle Measurements, two-terminal magnetoresistance), prior to > the development of spin manipulation and revolutionary spin devices. > > ** _ _** > > ** _Bibliography_** > > S. Roche, N. Leconte, F. Ortmann, A. Lherbier, D. Soriano, J.-Ch. Charlier, > _Quantum transport in disordered graphene: A theoretical perspective_ , > **Solid State Communications** , 152, 1404-1410 (2012) > > > > D. Soriano, N. Leconte, P Ordejon, J.-Ch. Charlier, J.-J. Palacios, and > **S. Roche** , _Magnetoresistance and Magnetic Ordering Fingerprints in > Hydrogenated Graphene_ , > > **Physical Review Letters** 107, 016602 (2011) > > > > A. Lherbier, S.M.M. Dubois, X. Declerck, Sr. Roche, Y.-M. Niquet and J.C. > Charlier, > > _Two-dimensional Graphene with Structural Defects: Elastic Mean Free Path, > Minimum Conductivity and Anderson_ > > **Physical Review Letters** , 106, 046803 (2011) > > > > T.Dinh et al, submitted for publication > >