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提出了含δ势垒的多臂量子环模型.研究发现总磁通为零时，持续电流随半导体环增大发生非周期性振荡，下臂因含δ势垒而获得最小的平均持续电流.AB磁通增强时，持续电流会发生周期性等幅振荡，并与电极的磁矩方向以及隧穿电子的自旋方向相关.两电极磁矩方向平行时，Rashba自旋轨道耦合具有改变持续电流相位和相位差的效应；两电极磁矩方向反平行时，Rashba自旋轨道耦合具有改变持续电流振幅的效应.各臂之间持续电流的不同与臂长和磁通分布的差异相关.在一定条件下，两种波函数所对应的持续电流是可分离的.
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关键词:
- 多臂量子环 /
- 持续电流 /
- δ势垒 /
- Rashba自旋轨道耦合
A new model of quantum ring with multiple arms containing δ barrier is proposed in this paper. The results imply that the persistent current shows behavior of nonperiodic oscillation with the size of the semiconductor ring increasing when the total magnetic flux is zero. The lower arm obtains minimal average persistent current because it contains the δ barrier. The persistent current generates periodic oscillation when the AB magnetic flux strengthens. It is related to not only the electrodes’ magnetic moment direction but also the tunneling electrons’ spin orientation. Furthermore, when the two magnetic moments are parallel, the Rashba spin-orbit interaction has the effect of changing the persistent current’s phase and phase difference. However, when the magnetic moments in the two electrodes are antiparallel, the Rashba spin-orbit interaction affects the amplitude of the persistent current. Our results also indicate that the difference of the persistent current in each arm is retated to the arm length and the magnetic flux’s distribution. The persistent currents which the two kind of wave functions correspond to are separated under definite conditions.-
Keywords:
- quantum ring with multiple arms /
- persistent current /
- δ barrier /
- Rashba spin-orbit interaction
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[2] ［2］Fiete G A,Hur K Le,Balents L 2005 Phys.Rev. B 72 125416
[3] ［3］Rodrigues V,Bettini J,Silva P C,Ugarte D 2003 Phys.Rev.Lett. 91 96801
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[6] ［6］Du J,Zhang P,Liu J H,Li J L,Li Y X 2008 Acta Phys.Sin. 57 7221(in Chinese)［杜坚、张鹏、刘继红、李金亮、李玉现 2008 57 7221］
[7] ［7］Yin Y Q,Li H,Ma J N,He Z L,Wang X Z 2009 Acta Phys.Sin. 58 4162(in Chinese)［尹永琦、李华、马佳宁、贺泽龙、王选章 2009 58 4162］
[8] ［8］Wu S Q 2009 Acta Phys.Sin. 58 4175(in Chinese)［吴绍全 2009 58 4175］
[9] ［9］Chen X W,Chen B J,Shi Z G,Song K H 2009 Acta Phys.Sin. 58 2720(in Chinese)［谌雄文、谌宝菊、施振刚、宋克慧 2009 58 2720］
[10] ］Ma M M,Ding J W,Chen H B,Xu N 2009 Acta Phys.Sin. 58 2726(in Chinese)［马明明、丁建文、陈宏波、徐宁 2009 58 2726］
[11] ］Du J,Li C G,Qin F 2009 Acta Phys. Sin. 58 576 (in Chinese)［杜坚、李春光、秦芳 2009 58 576］
[12] ］Governale M,Zülicke U 2002 Phys.Rev.B 66 073311
[13] ］Onoda M,Nagaosa N 2005 Phys.Rev.Lett. 95 106601
[14] ］Berry M V 1984 Proc. Roy. Soc. Lond.Ser. A 392 45
[15] ］Byers N,Yang C N 1961 Phys.Rev.Lett. 7 46
[16] ］Hammar P R,Bennett B R,Yang M J,Mark J 1999 Phys.Rev.Lett. 83 203
[17] ］Schmidt G 2000 Phys.Rev.B 62 R4790
[18] ］Alvorado S F 1995 Phys.Rev.Lett. 75 513
[19] ］Citro R, Romeo F, Marinaro M 2006 Phys.Rev. B 74 115329
[20] ］Sheng J S,Chang K 2006 Phys.Rev. B 74 235315
[21] ］Wang M,Chang K 2008 Phys.Rev. B 77 125330
[22] ］Meijer F E,Morpurgo A F,Klapwijk T M 2002 Phys.Rev.B 66 033107
[23] ］Molnar B,Peeters F M,Vasilopoulos P 2004 Phys.Rev.B 69 155335
[24] ］Wu H C,Guo Y,Chen X Y,Gu B L 2003 Phys.Rev.B 68 125330
-
[1] ［1］Balents L,Egger R 2000 Phys.Rev.Lett. 85 3464
[2] ［2］Fiete G A,Hur K Le,Balents L 2005 Phys.Rev. B 72 125416
[3] ［3］Rodrigues V,Bettini J,Silva P C,Ugarte D 2003 Phys.Rev.Lett. 91 96801
[4] ［4］Wang X F,Vasilopoulos P,Peeters F M 2005 Phys.Rev. B 71 125301
[5] ［5］Li Y X,Liu J J,Li B Z 2005 Acta Phys.Sin. 54 1366(in Chinese) ［李玉现、刘建军、李伯臧 2005 54 1366］
[6] ［6］Du J,Zhang P,Liu J H,Li J L,Li Y X 2008 Acta Phys.Sin. 57 7221(in Chinese)［杜坚、张鹏、刘继红、李金亮、李玉现 2008 57 7221］
[7] ［7］Yin Y Q,Li H,Ma J N,He Z L,Wang X Z 2009 Acta Phys.Sin. 58 4162(in Chinese)［尹永琦、李华、马佳宁、贺泽龙、王选章 2009 58 4162］
[8] ［8］Wu S Q 2009 Acta Phys.Sin. 58 4175(in Chinese)［吴绍全 2009 58 4175］
[9] ［9］Chen X W,Chen B J,Shi Z G,Song K H 2009 Acta Phys.Sin. 58 2720(in Chinese)［谌雄文、谌宝菊、施振刚、宋克慧 2009 58 2720］
[10] ］Ma M M,Ding J W,Chen H B,Xu N 2009 Acta Phys.Sin. 58 2726(in Chinese)［马明明、丁建文、陈宏波、徐宁 2009 58 2726］
[11] ］Du J,Li C G,Qin F 2009 Acta Phys. Sin. 58 576 (in Chinese)［杜坚、李春光、秦芳 2009 58 576］
[12] ］Governale M,Zülicke U 2002 Phys.Rev.B 66 073311
[13] ］Onoda M,Nagaosa N 2005 Phys.Rev.Lett. 95 106601
[14] ］Berry M V 1984 Proc. Roy. Soc. Lond.Ser. A 392 45
[15] ］Byers N,Yang C N 1961 Phys.Rev.Lett. 7 46
[16] ］Hammar P R,Bennett B R,Yang M J,Mark J 1999 Phys.Rev.Lett. 83 203
[17] ］Schmidt G 2000 Phys.Rev.B 62 R4790
[18] ］Alvorado S F 1995 Phys.Rev.Lett. 75 513
[19] ］Citro R, Romeo F, Marinaro M 2006 Phys.Rev. B 74 115329
[20] ］Sheng J S,Chang K 2006 Phys.Rev. B 74 235315
[21] ］Wang M,Chang K 2008 Phys.Rev. B 77 125330
[22] ］Meijer F E,Morpurgo A F,Klapwijk T M 2002 Phys.Rev.B 66 033107
[23] ］Molnar B,Peeters F M,Vasilopoulos P 2004 Phys.Rev.B 69 155335
[24] ］Wu H C,Guo Y,Chen X Y,Gu B L 2003 Phys.Rev.B 68 125330
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