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Proceedings Paper

Manipulation of the spin degrees of freedom in graphene nanoribbons (Conference Presentation)
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Paper Abstract

The recent proposal of cascading spin logic in low-dimensional carbon materials by Friedman et al. [1] has provided a new paradigm to perform efficient high-performance computing. In this scenario, graphene nanoribbon (GNR) transistors, in concert with metallic carbon nanotubes (CNT) interconnect, provide compact logic, low current requirements, and fast switching times. The idea is based on the recent discovery of CNT unzipping mechanisms and exceptional negative magnetoresistance in GNRs for which partially unzipped CNTs permit the development of an all-carbon spintronic logic family. In this talk, we describe the physical model that predicts the onset of spin polarization on zig-zag GNR edges in the presence of magnetic field. The model is based on a tight-binding Hamiltonian in the presence of non-local magnetic field with site-to-site interaction up to the third nearest neighbor. Coupled to a non-equilibrium green function (NEGF) formalism, our model shows electrons of opposing spin result in two stable states: a global antiferromagnetic (AFM) ground state with zero net magnetization, and a ferromagnetic (FM) state at a slightly higher energy with a net magnetization. Both magnetic states have local AFM ordering and large magnetization at the edge sites. A magnetic field arising from a current passing through a CNT close to the edge alters the GNR's magnetic energy via the Zeeman interaction. When the field is strong enough, the change of the GNR ground state from AFM to FM switches its electrical behavior from insulating to conducting. 1. J.S. Friedman et al., Nature Communications 8, 15635 (2017).

Paper Details

Date Published: 18 September 2018
Proc. SPIE 10732, Spintronics XI, 107321X (18 September 2018); doi: 10.1117/12.2320772
Show Author Affiliations
Jean-Pierre Leburton, Univ. of Illinois at Urbana-Champaign (United States)

Published in SPIE Proceedings Vol. 10732:
Spintronics XI
Henri-Jean Drouhin; Jean-Eric Wegrowe; Manijeh Razeghi; Henri Jaffrès, Editor(s)

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