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Title: Spin relaxation in graphene nanoribbons in the presence of substrate surface roughness

Abstract

In this work, spin transport in corrugated armchair graphene nanoribbons (AGNRs) is studied. We survey combined effects of spin-orbit interaction and surface roughness, employing the non-equilibrium Green's function formalism and multi-orbitals tight-binding model. Rough substrate surfaces have been statistically generated and the hopping parameters are modulated based on the bending and distance of corrugated carbon atoms. The effects of surface roughness parameters, such as roughness amplitude and correlation length, on spin transport in AGNRs are studied. The increase of surface roughness amplitude results in the coupling of σ and π bands in neighboring atoms, leading to larger spin flipping rate and therefore reduction of the spin-polarization, whereas a longer correlation length makes AGNR surface smoother and increases spin-polarization. Moreover, spin diffusion length of carriers is extracted and its dependency on the roughness parameters is investigated. In agreement with experimental data, the spin diffusion length for various substrate ranges between 2 and 340 μm. Our results indicate the importance of surface roughness on spin-transport in graphene.

Authors:
;  [1];  [2];  [2];  [3];  [4]
  1. Department of Electrical Engineering, Sharif University of Technology, Tehran 11365-8639 (Iran, Islamic Republic of)
  2. School of Electrical and Computer Engineering, University of Tehran, Tehran 14395-515 (Iran, Islamic Republic of)
  3. (IPM), Tehran 19395-5531 (Iran, Islamic Republic of)
  4. (Austria)
Publication Date:
OSTI Identifier:
22597690
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMPLITUDES; ATOMS; BENDING; CORRELATIONS; DIFFUSION; DIFFUSION LENGTH; GRAPHENE; GREEN FUNCTION; L-S COUPLING; NANOSTRUCTURES; RELAXATION; ROUGHNESS; SPIN; SPIN ORIENTATION; SUBSTRATES; SURFACES

Citation Formats

Chaghazardi, Zahra, Faez, Rahim, Touski, Shoeib Babaee, Pourfath, Mahdi, E-mail: pourfath@ut.ac.ir, E-mail: pourfath@iue.tuwien.ac.at, School of Nano Science, Institute for Research on Fundamental Sciences, and Institute for Microelectronics, Technische Universität Wien, Gußhausstraße 27–29/E360, A-1040 Wien. Spin relaxation in graphene nanoribbons in the presence of substrate surface roughness. United States: N. p., 2016. Web. doi:10.1063/1.4960354.
Chaghazardi, Zahra, Faez, Rahim, Touski, Shoeib Babaee, Pourfath, Mahdi, E-mail: pourfath@ut.ac.ir, E-mail: pourfath@iue.tuwien.ac.at, School of Nano Science, Institute for Research on Fundamental Sciences, & Institute for Microelectronics, Technische Universität Wien, Gußhausstraße 27–29/E360, A-1040 Wien. Spin relaxation in graphene nanoribbons in the presence of substrate surface roughness. United States. doi:10.1063/1.4960354.
Chaghazardi, Zahra, Faez, Rahim, Touski, Shoeib Babaee, Pourfath, Mahdi, E-mail: pourfath@ut.ac.ir, E-mail: pourfath@iue.tuwien.ac.at, School of Nano Science, Institute for Research on Fundamental Sciences, and Institute for Microelectronics, Technische Universität Wien, Gußhausstraße 27–29/E360, A-1040 Wien. Sun . "Spin relaxation in graphene nanoribbons in the presence of substrate surface roughness". United States. doi:10.1063/1.4960354.
@article{osti_22597690,
title = {Spin relaxation in graphene nanoribbons in the presence of substrate surface roughness},
author = {Chaghazardi, Zahra and Faez, Rahim and Touski, Shoeib Babaee and Pourfath, Mahdi, E-mail: pourfath@ut.ac.ir, E-mail: pourfath@iue.tuwien.ac.at and School of Nano Science, Institute for Research on Fundamental Sciences and Institute for Microelectronics, Technische Universität Wien, Gußhausstraße 27–29/E360, A-1040 Wien},
abstractNote = {In this work, spin transport in corrugated armchair graphene nanoribbons (AGNRs) is studied. We survey combined effects of spin-orbit interaction and surface roughness, employing the non-equilibrium Green's function formalism and multi-orbitals tight-binding model. Rough substrate surfaces have been statistically generated and the hopping parameters are modulated based on the bending and distance of corrugated carbon atoms. The effects of surface roughness parameters, such as roughness amplitude and correlation length, on spin transport in AGNRs are studied. The increase of surface roughness amplitude results in the coupling of σ and π bands in neighboring atoms, leading to larger spin flipping rate and therefore reduction of the spin-polarization, whereas a longer correlation length makes AGNR surface smoother and increases spin-polarization. Moreover, spin diffusion length of carriers is extracted and its dependency on the roughness parameters is investigated. In agreement with experimental data, the spin diffusion length for various substrate ranges between 2 and 340 μm. Our results indicate the importance of surface roughness on spin-transport in graphene.},
doi = {10.1063/1.4960354},
journal = {Journal of Applied Physics},
number = 5,
volume = 120,
place = {United States},
year = {Sun Aug 07 00:00:00 EDT 2016},
month = {Sun Aug 07 00:00:00 EDT 2016}
}