مقاومت مغناطیسی تنظیم‌پذیر در پیوندگاه گرافین گاف‌دار تحت کشش در حضور سد مغناطیسی

نوع مقاله: مقاله پژوهشی کامل

نویسنده

هیات علمی

چکیده

در تحقیق حاضر با اعمال هم‌زمان کشش و سد مغناطیسی به گرافین گاف‌دار که بین دو الکترود فرومغناطیسی قرار گرفته است ضریب عبور و رسانش پیوندگاه بررسی شده و شرایط رسیدن به بیشینه مقاومت مغناطیسی مهیا شده است. نتایج نشان می‌دهند اعمال کشش به تنهایی منجر به ایجاد گاف دره‌ای در ساختار گرافین نمی‌شود و این گاف با اعمال سد مغناطیسی در حضور کشش در ساختار گرافین قابل ایجاد و با تغییر مقدار گاف جرمی زیر لایه قابل کنترل و تنظیم است. همچنین نشان داده شده است که مقاومت مغناطیسی پیوندگاه به شدت به پارامترهای کشش اعمالی به گرافین، سد مغناطیسی، پیکربندی بردار مغناطش نواحی فرومغناطیس و گاف جرمی زیر لایه وابسته است به گونه-ای که با انتخاب مقادیر مناسبی برای پارامترهای مذکور، مقاومت مغناطیسی پیوندگاه به 100% می‌رسد. به طور مشخص برای دره K با تغییر پیکربندی از موازی به پادموازی با اعمال مقادیر مذکور، نمودار رسانش پادموازی سریع‌تر نسبت به نمودار رسانش موازی به صفر می‌رسد. در این شرایط پیوندگاه فقط برای پیکربندی رسانش موازی از خود عبور نشان می‌دهد که این امر منجر به بیشینه شدن مقاومت مغناطیسی پیوندگاه می‌شود. تنظیم‌پذیر بودن مقاومت مغناطیسی پیوندگاه نشان دهندۀ کاربرد آن در وسایل اسپین-الکترونیکی بر پایۀ گرافین است.

کلیدواژه‌ها


عنوان مقاله [English]

Tunable magnetoresistance in gapped graphene junction with strain and magnetic barrier

چکیده [English]

In this paper, by applying strain and magnetic barrier simultaneously in gapped graphene which has been located between two ferromagnetic electrodes, the transmission of the coefficient and conductance of the junction have been studied and the condition has been provided to reach giant magnetoresistance. The results show that the valley gap cannot be achieved in graphene only by using strain and it comes into being in strain graphene with magnetic barrier and it is controllable by changing substrate mass gap. Also, it is found that the MR strongly depends on the strain, magnetic barrier, magnetization configuration of the ferromagnetic regions, and substrate mass gap in a way that by applying appropriate values for these parameters, the MR can reach up to 100%. Specially, for K valley, by changing the configuration magnetization from parallel to antiparallel, the antiparallel conductance reduces to zero faster than the parallel conductance for the above parameters. So, the junction is transparent only for parallel conductance leading to an increase of MR to 100%. Tunability of the MR reveals the potential application of the proposed junction for future spin-electronics devices.

کلیدواژه‌ها [English]

  • Magnetoresistance
  • Strain
  • Magnetic barrier
  • Gapped graphene
[1] K.S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, Y. Zhang, S.V. Dubonos, I.V. Grigorieva, A.A. Firsov, Electric field effect in atomically thin carbon films, Science 306 (2004) 666.  

[2] K.S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, M.I. Katsnelson, I.V. Grigorieva, S.V. Dubonos, A.A. Firsov, Two-dimensional gas of massless Dirac fermions in graphene, Nature (London) 438 (2005) 197.

[3] M.I. Katsnelson, K.S. Novoselov, Graphene: new bridge between condensed matter physics and quantum electrodynamics, Solid State Commun. 143 (2007) 3.

[4] A.K. Geim, K.S. Novoselov, The rise of graphene, Nature Mater. 6 (2007) 183.

[5] M.I. Katsnelson, K.S. Novoselov, A.K. Geim, Chiral tunnelling and the Klein paradox in graphene, Nature Physics 2 (2006) 620.

[6] A.H. Castro Neto, F. Guinea, N.M.R. Peres, K.S. Novoselov, A.K. Geim, The electronic properties of graphene, Reviews of Modern Physics 81 (2009) 109.

[7] Q.P. Wu, Z.F. Liu, A.X. Shen, X.B. Xiao, Z.M. Liu, Full valley and spin polarizations in strained graphene with Rashba spin orbit coupling and magnetic barrier, Scientific Reports 6 (2016) 21590.

[8] M.M. Grujic, M.Z. Tadic, F.M. Peeters, Spin-Valley filtering in strained graphene structures with artificially induced carrier mass and spin-orbit coupling, Physical Review Letters 113 (2014) 046601.

[9] H. Haugen, D. Huertas-Hernando, A. Brataas, Spin transport in proximity-induced ferromagnetic graphene, Physical Review B 77 (2008) 115406.

[10] H.X. Yang, A. Hallal, D. Terrade, X. Waintal, S. Roche, M. Chshiev, Proximity effects induced in graphene by magnetic insulators: first-principles calculations on spin filtering and exchange-splitting gaps, Physical Review Letters 110 (2013) 046603.

[11] Z.F. Liu, Q.P. Wu, A.X. Chen, X.B. Xiao, N.H. Liu, Enhanced spin polarization in graphene with spin energy gap induced by spin-orbit coupling and strain, Journal of Applied Physics 115 (2014) 203710.

[12] Z. Cao, N. Lu, X. Qiu, G. Wang, Strain effect on spin polarization in a graphene junction, Journal of Physics: Condensed Matter 50 (2017) 13.

[13] E.H. Hwang, S. Das Sarma, Graphene magnetoresistance in a parallel magnetic field: Spin polarization effect, Physical Review B 80 (2009) 075417.

[14] H. Yu Tian, J. Wang, Spatial valley separation in strained graphene pn junction, Journal of Physics: Condensed Matter 29 (2017) 38.

[15] T. Farajollahpor, A. Phirouznia, The role of the strain induced population imbalance in Valley polarization of graphene: Berry curvature perspective, Scientific Reports 7 (2017) 17878.

[16] H. Mophammadpour, K. Hasanirokh, Magnetoresistance in Graphene-Based Ferromagnetic/ Rashba Barrier/Ferromagnetic Heterojunction, Acta Physica Polonica A 129 (2016) 1.

[17] C. Bai, J.T. Wang, S.W. Jia, Y.L. Yand, Spin-orbit interaction effects on magnetoresistance in graphene-based ferromagnetic double junctions,Applied Physics Letters 96 (2010) 223102.

[18] J. Bai, et al, Very large magnetoresistance in graphene nanoribbons, Nature Nanotechnology, 5 (2010) 655.

[19] J.M. Lu, H.J. Zhang, W. Shi, Z. Wang, Y. Zhang, T. Zhang, N. Wang, Z.K. Tang, P. Sheng, Graphene Magnetoresistance Device in van der Pauw Geometry, Nano Letters 11 (2011) 2973.

[20] A.L. Friedman, Joseph L. Tedesco, et al., Quantum linear magnetoresistance in multilayer epitaxial graphene, Nano Letters10 (2010) 3962.

[21] Z.M. Liao, H.C. Wu, J.J. Wang, G.L. W. Cross, S. Kumar, I.V. Shvets, G.S. Duesberg, Magnetoresistance of Fe3O4-graphene- Fe3O4 junctions, Applied Physics Letters 98 (2011) 052511.

[22] E.W. Hill, A.K. Geim, K. Novoselov, F. Schedin, P. Blake, Graphene spin valve devices, IEEE Transactions on Magnetics 42 (2006) 2694. 

[23] J. Wang, M. Long, W. Zhao, Y. Hu, G. Wang, K.S. Chan, A valley and spin filter based on gapped graphene, Journal of Physics: Condensed Matter 28 (2016) 285302.

[24] V.V. Cheianov, V.I. Falko, Selective transmission of Dirac electrons and ballistic magnetoresistance of n−p junctions in graphene, Physical Review B 74 (2006) 041403(R).

[1] K.S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, Y. Zhang, S.V. Dubonos, I.V. Grigorieva, A.A. Firsov, Electric field effect in atomically thin carbon films, Science 306 (2004) 666.  

[2] K.S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, M.I. Katsnelson, I.V. Grigorieva, S.V. Dubonos, A.A. Firsov, Two-dimensional gas of massless Dirac fermions in graphene, Nature (London) 438 (2005) 197.

[3] M.I. Katsnelson, K.S. Novoselov, Graphene: new bridge between condensed matter physics and quantum electrodynamics, Solid State Commun. 143 (2007) 3.

[4] A.K. Geim, K.S. Novoselov, The rise of graphene, Nature Mater. 6 (2007) 183.

[5] M.I. Katsnelson, K.S. Novoselov, A.K. Geim, Chiral tunnelling and the Klein paradox in graphene, Nature Physics 2 (2006) 620.

[6] A.H. Castro Neto, F. Guinea, N.M.R. Peres, K.S. Novoselov, A.K. Geim, The electronic properties of graphene, Reviews of Modern Physics 81 (2009) 109.

[7] Q.P. Wu, Z.F. Liu, A.X. Shen, X.B. Xiao, Z.M. Liu, Full valley and spin polarizations in strained graphene with Rashba spin orbit coupling and magnetic barrier, Scientific Reports 6 (2016) 21590.

[8] M.M. Grujic, M.Z. Tadic, F.M. Peeters, Spin-Valley filtering in strained graphene structures with artificially induced carrier mass and spin-orbit coupling, Physical Review Letters 113 (2014) 046601.

[9] H. Haugen, D. Huertas-Hernando, A. Brataas, Spin transport in proximity-induced ferromagnetic graphene, Physical Review B 77 (2008) 115406.

[10] H.X. Yang, A. Hallal, D. Terrade, X. Waintal, S. Roche, M. Chshiev, Proximity effects induced in graphene by magnetic insulators: first-principles calculations on spin filtering and exchange-splitting gaps, Physical Review Letters 110 (2013) 046603.

[11] Z.F. Liu, Q.P. Wu, A.X. Chen, X.B. Xiao, N.H. Liu, Enhanced spin polarization in graphene with spin energy gap induced by spin-orbit coupling and strain, Journal of Applied Physics 115 (2014) 203710.

[12] Z. Cao, N. Lu, X. Qiu, G. Wang, Strain effect on spin polarization in a graphene junction, Journal of Physics: Condensed Matter 50 (2017) 13.

[13] E.H. Hwang, S. Das Sarma, Graphene magnetoresistance in a parallel magnetic field: Spin polarization effect, Physical Review B 80 (2009) 075417.

[14] H. Yu Tian, J. Wang, Spatial valley separation in strained graphene pn junction, Journal of Physics: Condensed Matter 29 (2017) 38.

[15] T. Farajollahpor, A. Phirouznia, The role of the strain induced population imbalance in Valley polarization of graphene: Berry curvature perspective, Scientific Reports 7 (2017) 17878.

[16] H. Mophammadpour, K. Hasanirokh, Magnetoresistance in Graphene-Based Ferromagnetic/ Rashba Barrier/Ferromagnetic Heterojunction, Acta Physica Polonica A 129 (2016) 1.

[17] C. Bai, J.T. Wang, S.W. Jia, Y.L. Yand, Spin-orbit interaction effects on magnetoresistance in graphene-based ferromagnetic double junctions,Applied Physics Letters 96 (2010) 223102.

[18] J. Bai, et al, Very large magnetoresistance in graphene nanoribbons, Nature Nanotechnology, 5 (2010) 655.

[19] J.M. Lu, H.J. Zhang, W. Shi, Z. Wang, Y. Zhang, T. Zhang, N. Wang, Z.K. Tang, P. Sheng, Graphene Magnetoresistance Device in van der Pauw Geometry, Nano Letters 11 (2011) 2973.

[20] A.L. Friedman, Joseph L. Tedesco, et al., Quantum linear magnetoresistance in multilayer epitaxial graphene, Nano Letters10 (2010) 3962.

[21] Z.M. Liao, H.C. Wu, J.J. Wang, G.L. W. Cross, S. Kumar, I.V. Shvets, G.S. Duesberg, Magnetoresistance of Fe3O4-graphene- Fe3O4 junctions, Applied Physics Letters 98 (2011) 052511.

[22] E.W. Hill, A.K. Geim, K. Novoselov, F. Schedin, P. Blake, Graphene spin valve devices, IEEE Transactions on Magnetics 42 (2006) 2694. 

[23] J. Wang, M. Long, W. Zhao, Y. Hu, G. Wang, K.S. Chan, A valley and spin filter based on gapped graphene, Journal of Physics: Condensed Matter 28 (2016) 285302.

[24] V.V. Cheianov, V.I. Falko, Selective transmission of Dirac electrons and ballistic magnetoresistance of n−p junctions in graphene, Physical Review B 74 (2006) 041403(R).