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Prediction of very large values of magnetoresistance in a graphene nanoribbon device

Nature Nanotechnology volume 3, pages 408412 (2008) | Download Citation

Abstract

Graphene has emerged as a versatile material with outstanding electronic properties1,2,3,4 that could prove useful in many device applications. Recently, the demonstration of spin injection into graphene and the observation of long spin relaxation times and lengths have suggested that graphene could play a role in ‘spintronic’ devices that manipulate electron spin rather than charge5,6,7,8. In particular it has been found that zigzag graphene nanoribbons have magnetic (or spin) states at their edges, and that these states can be either antiparallel or parallel9,10,11,12,13,14,15,16. Here we report the results of first-principles simulations that predict that spin-valve devices based on graphene nanoribbons will exhibit magnetoresistance values that are thousands of times higher than previously reported experimental values17,18,19. These remarkable values can be linked to the unique symmetry of the band structure in the nanoribbons. We also show that it is possible to manipulate the band structure of the nanoribbons to generate highly spin-polarized currents.

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Acknowledgements

This work was supported by the Global Research Lab Project (KICOS) and Brain Korea 21. We thank M. L. Cohen, Y.H. Kim, Y. Son, J.H. Shim, B.I. Min, H.W. Lee, S.K. Kwon and A.W. Leonard for reading the manuscript and providing comments. Calculations were performed with KISTI supercomputers.

Author information

Affiliations

  1. Department of Chemistry, Center for Superfunctional Materials, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea

    • Woo Youn Kim
    •  & Kwang S. Kim
  2. Department of Physics, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea

    • Kwang S. Kim

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Contributions

W.Y.K. and K.S.K. conceived and designed the simulations. W.Y.K. developed the program code used in the transmission calculations and performed the calculations. W.Y.K. and K.S.K. discussed the results and co-wrote the paper.

Corresponding author

Correspondence to Kwang S. Kim.

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DOI

https://doi.org/10.1038/nnano.2008.163

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