单层正三角锯齿型石墨烯量子点的电子结构和磁性

潘洪哲; 徐明; 陈丽; 孙媛媛; 王永龙

doi:10.7498/aps.59.6443

摘要

采用基于密度泛函理论的广义梯度近似(GGA),对不同尺寸(N=2—11)的单层正三角锯齿型石墨烯量子点(ZN -GNDs)的结构进行优化,得到与实验数据较好符合的晶格常数,进一步计算得到不同尺寸下体系的自旋多重度、磁矩、电子态密度以及自旋电子密度.结果表明:所有体系都呈现金属性,在尺寸较小的体系中量子尺寸效应对电子结构的影响比较明显;与单层石墨烯片一样,sp2杂化作用和非键态电子在量子点中仍起到非常重要的作用;费米能级上有自旋向上的电子分布,体系的

关键词:

石墨烯 /
量子点 /
电子结构 /
磁性

Abstract

The geometry, spin multiplicity, magnetic moment, electronic density of states and the spin density of single-layer trigonal graphene quantum dots with zigzag edges have been systematically investigated using density functional theory with the generalized gradient approximation under different sizes. The calculated results such as lattice constants are in good agreement with experimental data and indicate that the system behaves like metal, while the electrons with up spins occupy the Fermi energy. The influence of quantum size effect is remarkable in the system of small size. It is also found that the sp2 hybridization and nonbonding electrons play an important part in the single-layer trigonal graphene quantum dots, just like in graphene. The spin multiplicity and magnetic moment of the system increase with the increase of the system size. Based on our calculation, the total magnetic moment of the system mainly comes from the nonbonding electrons on the 2p orbital of the zigzag boundary. Our calculation may be helpful in designing devices based on trigonal graphene quantum dots.

Keywords:

作者及机构信息

(1)临沂师范学院理学院,临沂 276005; (2)临沂师范学院理学院,临沂 276005;四川师范大学物理与电子工程学院和固体物理研究所,成都 610068; (3)四川师范大学物理与电子工程学院和固体物理研究所,成都 610068

基金项目: 国家自然科学基金(批准号: 10974076)和山东省自然科学基金(批准号: Y2008A14)资助的课题.

Authors and contacts

(1)Institute of Solid State Physics & School of Physics and Electronic Engineering,Sichuan Normal University,Chengdu 610068,China; (2)School of Sciences,Linyi Normal University,Linyi 276005,China; (3)School of Sciences,Linyi Normal University,Linyi 276005,China;Institute of Solid State Physics & School of Physics and Electronic Engineering,Sichuan Normal University,Chengdu 610068,China

参考文献

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施引文献

[1]	Novoselov K S, Geim A K, Morozov S V, Jiang D, Zhang Y, Dubonos S V, Grigorieva I V, Firsov A A 2004 Science 306 666
[2]	Novoselov K S, Geim A K, Morozov S V, Jiang D, Katsnelson M I, Grigorieva I V, Dubonos S V, Firsov A A 2005 Nature 438 197
[3]	Zhang Y B, Tan Y W, Stormer H L, Kim P 2005 Nature 438 201
[4]	Tan C L, Tan Z B, Ma L, Chen J, Yang F, Qu F M, Liu G T, Yang H F, Yang C L, Lü L 2009 Acta Phys. Sin. 58 5726 (in Chinese) [谭长玲、谭振兵、马丽、陈军、杨帆、屈凡明、刘广同、杨海方、杨昌黎、吕力 2009 物理学报 58 5726]
[5]	Hu H X, Zhang Z H, Liu X H, Qiu M, Ding K H 2009 Acta Phys. Sin. 58 7165 (in Chinese) [胡海鑫、张振华、刘新海、邱明、丁开和 2009 物理学报 58 7165]
[6]	Tombros N, Jozsa C, Popinciuc M, Jonkman H T, Wees B J 2007 Nature 448 571
[7]	Ouyang F P, Xu Hui, Wei Chen 2008 Acta Phys. Sin. 57 1073 (in Chinese) [欧阳方平、徐慧、魏辰 2008 物理学报 57 1073]
[8]	Novoselov K S, Jiang Z, Zhang Y, Morozov S V, Stormer H L, Zeitler U, Maan J C, Boebinger G S, Kim P, Geim A K 2007 Science 315 1379
[9]	Ci L, Xu Z, Wang L, Gao W, Ding F, Kelly K F, Yakobson B I, Ajayan P M 2008 Nano Res. 1 116
[10]	Ezawa M 2006 Phys. Rev. B 73 045432
[11]	Son Y W, Cohen M L, Louie S G 2006 Phys. Rev. Lett. 97 216803
[12]	Cervantes S F, Csányi G, Piscanec S, Ferrari A C 2008 Phys. Rev. B 77 165427
[13]	Ezawa M 2008 Phys. Rev. B 77 155411
[14]	Wang W L, Meng S, Kaxiras E 2008 Nano Lett. 8 241
[15]	Fernández R J, Palacios J J 2007 Phys. Rev. Lett. 99 177204
[16]	Ezawa M 2007 Phys. Rev. B 76 245415
[17]	Di C A, Wei D C, Yu G, Liu Y Q, Guo Y L, Zhu D B 2008 Adv. Mater. 20 3289
[18]	Wei D C, Liu Y Q, Zhang H L, Huang L P, Wu B, Chen J Y, Yu G 2009 J. Am. Chem. Soc. 131 11147
[19]	Geim A K 2009 Science 324 530
[20]	Westervelt R M 2008 Science 320 324
[21]	Son Y, Cohen M L, Louie S G 2006 Nature 444 347
[22]	Kobayashi Y, Fukui K, Enoki T, Kusakabe K, Kaburagi Y 2005 Phys. Rev. B 71 193406
[23]	Elias D C, Nair R R, Mohiuddin T M G, Morozov S V, Blake P, Halsall M P, Ferrari A C, Boukhvalov D W, Katsnelson M I, Geim A K, Novoselov K S 2009 Science 323 610
[24]	Perdew J P, Burke K, Ernzerhof M 1996 Phys. Rev. Lett. 77 3865
[25]	Perdew J P, Wang Y 1992 Phys. Rev. B 45 13244
[26]	Delley B 1990 J. Chem. Phys. 92 508
[27]	Delley B 2000 J. Chem. Phys. 113 7756
[28]	Girit  , Meyer J C, Erni R, Rossell M D, Kisielowski C, Yang L, Park C H, Crommie M F, Cohen M L, Louie S G, Zettl A 2009 Science 323 1705
[29]	Huang L F, Li Y L, Ni M Y, Wang X L, Zhang G R, Zeng Z 2009 Acta Phys. Sin. 58 S306 (in Chinese) [黄良锋、李延龄、倪美燕、王贤龙、张国仁、曾雉 2009 物理学报 58 S306]
[30]	Lee C G, Wei X D, Kysar J W, Hone J 2008 Science 321 385
[31]	Yang Z, Yan Y L, Zhao W J, Lei X L, Ge G X, Luo Y H 2007 Acta Phys. Sin. 56 2590 (in Chinese) [杨致、闫玉丽、赵文杰、雷雪玲、葛桂贤、罗有华 2007 物理学报 56 2590]
[32]	Zheng X H, Dai Z X, Wang X L, Zeng Z 2009 Acta Phys. Sin. 58 S259 (in Chinese) [郑小宏、戴振翔、王贤龙、曾熊 2009 物理学报 58 S259]
[33]	Lieb E H 1989 Phys. Rev. Lett. 62 1201

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