跳到主要內容

臺灣博碩士論文加值系統

(18.204.56.185) 您好!臺灣時間:2022/08/14 02:32
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果 :::

詳目顯示

我願授權國圖
: 
twitterline
研究生:郭華丞
研究生(外文):Watson Kuo
論文名稱:微小超導穿隧接合的磁通、電荷與自旋傳輸
論文名稱(外文):Vortex, Charge and Spin Transports in Small Superconducting Tunnel Junctions
指導教授:果尚志陳啟東陳啟東引用關係
指導教授(外文):Felix Shang-Jr GwoChiiDong Chen
學位類別:博士
校院名稱:國立清華大學
系所名稱:物理學系
學門:自然科學學門
學類:物理學類
論文種類:學術論文
論文出版年:2002
畢業學年度:90
語文別:中文
論文頁數:149
中文關鍵詞:微小超導穿隧接合一維陣列超導-絕緣體相變單電子電晶體超導自旋堆積
外文關鍵詞:small Josephson junctionsone-dimensional arrayssuperconductor-insulator phase transitionsingle electron transistorssuperconductivityspin accumulation
相關次數:
  • 被引用被引用:0
  • 點閱點閱:220
  • 評分評分:
  • 下載下載:0
  • 收藏至我的研究室書目清單書目收藏:1
本論文針對兩方面研究微小超導穿隧接合的磁通,電荷與自旋傳輸。其一是約瑟芬結的整體行為,其二是超導單電子電晶體中的自旋堆積。在第一部分我們研究約瑟芬結串聯組成的一維陣列,觀察其中由磁場所引發的的超導-絕緣體相變。此相變的臨界磁場,和電流-電壓特性曲線中所觀察到庫柏電對的庫倫阻斷,可相互對應。我們利用一維的超流-絕緣體理論來分析測量的電阻訊號。相變的度規分析提供我們該相變的臨界指數。
我們發現動力學指數$z$接近於1,而相關長度指數$\nu$在兩組樣品分別得到是0.3和0.45。這些結果可以提供我們一維約瑟芬結陣列中超導-絕緣體相變的相圖。該相圖以約瑟芬耦合強度和耗散強度來兩種參數表示。第二部分我們研究磁性/超導/磁性單電子電晶體的自旋堆積現象。
我們發現當兩磁性電極的磁化方向反平行排列時,超導的能隙會突然的減小。此能隙減少的效應會隨著外加源汲極電壓的增加而增強。能隙減少可以解釋為自旋堆積的影響,當磁性電極的磁化方向反平行排列時自旋堆積便發生。理論上可以自洽的考慮電荷效應和能隙減少的效應,給出結果與實驗比較。我們也考慮了閘極電壓對自旋堆積的影響。理論上閘極可以調控通過磁性單電子電晶體電流的偏極性。在實際應用上,我們討論了自旋翻轉散射和能量弛豫等等會削弱自旋堆積現象的物理過程。

We study vortex, charge and spin transport in small superconducting tunnel junctions in two aspects, the collective behavior of small Josephson junctions, and the spin accumulation in superconducting single electron transistors. For the first part, we experimentally study the magnetic field-induced superconductor-insulator quantum phase transition in one-dimensional arrays of small Josephson junctions. It is found that the critical magnetic field that separates the two
phases corresponds to the onset of Coulomb blockade of Cooper pairs tunneling in the current-voltage characteristics. The resistance data are analyzed in the context of the superfluid-insulator transition in one dimension, and a finite temperature scaling analysis isperformed to extract the critical exponents. The dynamical exponents $z$ are determined to be close to 1, and the correlation length exponents $\nu$ are found to be approximately 0.3 and 0.45 in the two groups of measured samples. We also construct an experimental phase diagram using Josephson coupling-to-charging energy ratio($E_J/E_{CP}$) and dissipation strength. For the second part, we both experimentally and theoretically study the spin accumulation in ferromagnet/superconductor/ferromagnet single electron transistors. The measured superconducting
gap as a function of magnetic field reveals a dramatic decrease when the magnetizations of the two leads are in nearly anti-parallel orientations. The effect of suppression increases with increasing source-drain voltage. This phenomena can be account for the spin accumulation, which takes place
when the ferromagnetic leads are in anti-parallel alignment, suppressing superconductivity in the central island. A comparison with theoretical calculations, in which the charging effect and gap suppression are self-consistently considered is presented. We also theoretically investigated the
spin accumulation under the influence of gate voltage. It is found that the gate can be used to tune polarization of current passing through the ferromagnetic single electron transistor when spin accumulates. Processes that weaken this phenomena such as spin-flipping and energy relaxation are
modeled and discussed.

Abstract ...iii
Table of Contents ...viii
1 Introduction ...1
1.1 Vortices, charges and spins ...1
1.2 JJA: from2D to 1D ...3
1.3 Interplay between spins and charges: FSETs ...8
2 1DJJA: Theoretical Overview ...15
2.1 Dynamics of a single Josephson junction ...15
2.2 Electro-statics and charge screening length...20
2.3 LC transmission line and charge soliton picture...24
2.4 Non-interacting model of 1DJJA...26
2.5 Phase transitions in 2D XY model...31
2.6 Effective two level system ...33
2.7 Gate charge effect...35
2.8 Effect of dissipation ...35
3 1DJJA: Experimental Results ...39
3.1 Introduction ...39
3.2 Fabrication ...40
3.3 Measurement setup...42
3.4 Current-voltage characteristics ...45
3.5 Temperature dependence ...54
3.6 Theoretical model and phase diagram ...55
3.7 Scaling...60
3.8 Conclusion...64
4 FSET: Results of Simulations 67
4.1 Introduction ...67
4.2 Spin dependent transport ...68
4.3 Charging effect ...69
4.4 The master equation for a SET ...73
4.5 Spin dependent charge states ...75
4.6 F/N/F SET: polarizations of current ...79
4.7 Co-tunneling ... 84
4.8 Spin polarizer ... 87
4.9 F/S/F SET: spin chemical potentials ...89
4.10 Suppression of superconducting gap ...92
4.11 Conclusion ...95
5 Suppression of Superconductivity by Spin Imbalance ...101
5.1 Introduction ...101
5.2 Sample fabrication ...102
5.3 V (H) hysteresis ... 105
5.4 Parameters fitting ...107
5.5 Voltage dependence of the superconducting gap ...110
5.6 Important time scales ...114
5.7 Stray fields ... 115
5.8 Relaxation of magnetizations...117
5.9 Conclusion ...120
6 General Conclusion ...121
Appendix ...125
Bibliography ...132

Watson Kuo and C.D. Chen, Phys. Rev. Lett., 87, 186804 (2001)
Watson Kuo and C.D. Chen, Phys. Rev. B 65, 104427(2002)
C. D. Chen, Watson Kuo, D. S. Chung, J. H. Shyu, and C. S. Wu, Phys. Rev. Lett., 88, 047004(2002)
L. J. Geerligs, M. Peters, L. E. M. de Groot, A. Verbruggen, and J. E. Mooij, Phys. Rev. Lett. 63, 326(1989)
H. S. J. van der Zant, F. C. Fritschy, W. J. Elion, L. J.
Geerligs, and J. E. Mooij, Phys. Rev. Lett. 69, 2971(1992)
C. D. Chen, P. Delsing, D. B. Haviland, Y. Harada, and T. Claeson, Phys. Rev. B {51},15645(1995)
J. M. Kosterlitz and D. J. Thouless, J. Phys. C {6},
1181(1973); J. M. Kosterlitz, J. Phys. C {7}, 1046(1974)
T. J. Shaw, M. J. Ferrari L. L. Sohn, D. H. Lee, M. Tinkham, and J. Clarke, Phys. Rev. Lett. {76}, 2551(1996)
L. S. Kuzmin, P. Delsing, T. Claeson, and K. K. Likharev, Phys. Rev. Lett. {62}, 2539(1989); P. Delsing, K. K. Likharev, L. S. Kuzmin, and T. Claeson, Phys. Rev. Lett. {63}, 1861(1989)
D. B. Haviland and P. Delsing, Phys. Rev. B {54} R6857 (1996)
E. Chow, P. Delsing, and D. B. Haviland, Phys. Rev. Lett.
{81}, 204(1998); P. Agren, K. Andersson and D. B. Haviland, J.
Low Temp. Phys. {124}, 291(2001)
A. van Oudenaarden and J. E. Mooij, Phys. Rev. Lett.
{76}, 4947(1996); A. van Oudenaarden, S. J. K. Vardy and J. E. Mooij, Phys. Rev. Lett.{77}, 4257(1996)
N. Giordano, Phys. Rev. Lett. {61}, 2137(1988); N. Giordano and E. R. Schuler, Phys. Rev. Lett.{63}, 2417(1989)
C. N. Lau, N. Markovic, M. Bockrath, A. Bezryadin, and M. Tinkham, Phys. Rev. Lett. {87}, 217003(2001)
N. D. Mermin and H. Wagner, Phys. Rev. Lett. {17}, 1133 (1966).
P. M. Tedrow and R. Meservey, Phys. Rev. Lett. {26}, 192(1971);
M. Johnson and R. H. Silsbee, Phys. Rev. Lett. {55}, 1790(1985); M. Johnson, Phys. Rev. Lett. {70} 2142 (1993)
N.-C. Yeh R. P. Vasquez, C. C. Fu, A. V. Samoilov, Y. Li, and K. Vakili, Phys. Rev. B {60}, 10522(1999)
K. Lee, W. Wang, I. Iguchi, B. Friedman, T. Ishibashi and K. Sato, Appl. Phys. Lett. {\bf 75}, 1149 (1999)
V. A. Vas’ko, V. A. Larkin, P. A. Kraus, K. R. Nikolaev, D.E. Grupp, C. A. Nordman, and A. M. Goldman, Phys. Rev. Lett. {78}, 1134 (1997)
Z. W. Dong, R. Ramesh, T. Venkatesan, M. Johnson, Z. Y. Chen, S. P. Pai,V. Talyansky, R. P. Sharma, R. Shreekala, C. J. Lobb,
and R. L. Greene, Appl. Phys. Lett., {71}, 1718 (1997)
S. K. Upadhyay, A. Palanisami, R. N. Louie, and R. A. Buhrman, Phys. Rev. Lett. {81}, 3247(1998)
R. J. Soulen Jr., J. M. Byers, M. S. Osofsky, B. Nadgorny, T. Ambrose, S. F. Cheng, P. R. Broussard, C. T. Tanaka, J. Nowak,
J. S. Moodera, A. Barry, and J. M. D. Coey, Science {282}, 85(1998)
K. Ono, H. Shimada, S. Kobayashi, and Y. Outuka, J. Phys.
Soc. Jpn. {65}, 3449(1996); K. Ono, H. Shimada, and Y. Outuka, J. Phys. Soc. Jpn. {66}, 1261(1997); K. Ono, H. Shimada, and Y. Ootuka, J. Phys.Soc. Jpn. {67}, 2852(1998)
H. Imamura, S. Takahashi and S. Maekawa, Phys. Rev. B, {59},
6017(1999); S. Takahashi and S. Maekawa, Phys. Rev. Lett. {80}, 1758(1998)
A. N. Korotkov and V. I. Safarov, Phys. Rev. B {59}, 89(1999)
A. Brataas, Yu. V. Nazarov, J. Inoue, G. E. W. Bauer, Phys. Rev. B,{59}, 93, (1999);
K. Tsukagoshi, B. W. Alphenaar, and H. Ago, Nature {401}, 572(1999)
C.-M. Hu, J. Nitta, A. Jensen, J. B. Hansen, and H. Takayanagi, Phys. Rev. B {63} 125333(2001)
chapter 2
K. K. Likharev and A. B. Zorin, J. Low Temp. Phys. {59}, 347(1985)
A. J. Legget, S. Chakravarty, A. T. Dorsey, Matthew P. A. Fisher, Anupam Garg, and W. Zwerger, Rev. Mod. Phys, {59}, 1(1987).
Z. Hermon, E. Ben-Jacob, and G. Schon, Phys. Rev. B {54} 1234(1996)
R. M. Bradley and S. Doniach, Phys. Rev. B {30},1138 (1984)
C. Bruder, R. Fazio, and G. Schon, Phys. Rev. B {47} 342(1993)
\H. J. Schulz, Phys. Rev. B {22} 5274(1980)
V. Ambegaokar, U. Eckern, and G. Schon, Phys. Rev. Lett. {48}, 1745 (1982)
W. Zerger, Europhys. Lett, {9}, 421(1989)
P. A. Bobbert, R. Fazio, G. Schon, and A. D. Zaikin, Phys. Rev. B {45}, 2294(1992)
A. B. Zorin, Phys. Rev. Lett. {76}, 4408(1996)
chapter 3
S. L. Sondhi, S. M. Girvin, J. P. Carini, and D. Shahar,
Rev. Mod. Phys. {69}, 315(1997)
S. E. Korshunov, Europhys. Lett. {9}, 107(1989);
G. J. Dolan, Appl. Phys. Lett. {31}, 337 (1977); T. A. Fulton and G. J. Dolan, Phys. Rev. Lett. {59}, 109(1987)
P. Delsing, T. Claeson, K. K. Likharev, and L. S. Kuzmin,
Phys. Rev. B {42}, 7439(1990)
J. S. Penttila, U. Parts, P. J. Hakonen, M. A. Paalanen, and E. B. Sonin, Phys. Rev. Lett. {82}, 1004(1999)
D. V. Averin and Yu. V. Nazarov, Phys. Rev. Lett. {65}, 2446(1990)
G. Falci, G. Schon, and G. T. Zimanyi, Phys. Rev. Lett. {74}, 3257(1995)
P. Delsing, C. D. Chen, D. B. Haviland, Y. Harada, and T. Claeson, Phys. Rev. B {50}, 3959(1994)
H. Grabert and U. Weiss, Phys. Rev. Lett. {53}, 1787
(1984);T. S. Tighe, A. T. Johnson, and M. Tinkham, Phys. Rev. B. {44}, 10286 (1991)
M. P. A. Fisher, G. Grinstein, and S. M. Girvin, Phys. Rev.
Lett. {64}, 587(1990); M.C. Cha, M. P. A. Fisher, S. M. Girvin, M.Wallin, and A. P. Young, Phys. Rev. B {44}, 6883(1991)
M. P. A. Fisher, P. B. Weichman, G. Grinstein, and D. S.
Fisher, Phys. Rev. B {40}, 546(1989)
chapter 4
J. Barnas and A. Fert, Phys. Rev. Lett, {80}, 1058(1998);
J. Barnas and A. Fert, Europhys. Lett. {44}, 85(1998);
J. Barnas and A. Fert, J. Magn. Magn. Mater., {\bf 192}, L391(1999)
J. Barna\'{s}, J. Martinek, G. Michal ek, B. R. Bul ka, and A.
Fert, Phys. Rev. B {62}, 12363(2000)
K. Majumdar and S. Hershfield, Phys. Rev. B, {57}, 11521 (1998)
X. H. Wang and A. Brataas, Phys. Rev. Lett. {83}, 5138 (1999);
A. Brataas and X. H. Wang, Phys. Rev. B. {64}, 104434(2001)
R. Meservey and P. M. Tedrow, Phys. Rep. {238}, 173 (1994)
{ Single Charge Tunneling}, NATO ASI Vol. 294, edited by H. Grabert and M. H. Devoret (Plenum Press, New York, 1992).
D. V. Averin, A. N. Korotkov, A. J. Manninen, and J. P. Pekola,
Phys. Rev. Lett. {78}, 4821 (1997).
S. Takahashi, H. Imamura, and S. Maekawa, Phys. Rev. Lett.
{82}, 19, 3911(1999); S. Takahashi, H. Imamura, and S. Maekawa, J. Appl. Phys. {87}, 9, 5227 (2000).
chapter 5
Z. Zheng, D. Y. Xing, G. Sun, and J. Dong, Phys. Rev. B {\bf 62}, 14326, (2000).
M. Johnson and R. H. Silsbee, Phys. Rev. B {37}, 5326 (1988)
R. Meservey, P. M. Tedrow and R. C. Bruno, Phys. Rev. B {11}, 4224 (1975).
T. W. Clinton and M. Johnson, Appl. Phys. Lett. {70}, 1170 (1997);T. W. Clinton and M. Johnson, J. Appl. Phys. {85}, 1637 (1999).
P. Grutter, H. I. Mamin, and D. Rugar, {Scanning Tunneling
Microscopy} II (R. Wiesendanger and H. -I. Gunterodt., eds.) Vol. 28, pp. 151-207, Springer-Verlag, Berlin, 1992.
J.S. Moodera, L. R. Kinder, T. M. Wong, and R. Meservey,
Phys. Rev. Lett. {74}, 3273 (1995).
D.V. Averin and K. K. Likharev, in {Mesoscopic Phenomena
in Solid}, P. 192, Ed. B.L. Altshuler, P.A. Lee, and R.A. Webb.
W. Wernsdorfer, K. Hasselbach, A. Sulpice, A. Benoit, J.-E.
Wegrowe, L. Thomas, B. Barbara and D. Mailly, Phys. Rev. B. {53}, 3341(1996).
conclusion
P. W. Anderson, J. Phys. Chem. Solids {11}, 28(1959).
D. C. Ralph, C. T. Black, and M. Tinkham, Phys. Rev. Lett. {78}, 4087 (1997).
A. J. Rimberg, T. R. Ho, C. Kurdak, J. Clarke, K. L. Campman
and A. C. Gossard,Phys. Rev. Lett. {78}, 2632 (1997).
Y. Takahide, R. Yagi, A. Kanda, Y. Ootuka and S. Kobayashi, Phys. Rev. Lett.{85}, 1974 (2000).

QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top