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Based on the Bogoliubov-de Gennes equations, we investigate the transport of the Josephson current in a one-dimensional S/FL-F-FR/S junction, where S and F are superconductor and ferromagnet, and FL,R are the left and right interfaces with noncollinear magnetizations. It is found that the FL and FR interfaces can induce spin-mixing and spin-flip effects, which can transform a part of spin-singlet pairs in the S into equal-spin triplet pairs in the F. For the short S/FL-F-FR/S junction, the spin-singlet pairs and the equal-spin triplet pairs can survive in the F layer. Therefore, with the increase of the ferromagnetic exchange field and the angle difference of interface magnetization rotation, the critical current oscillates on a base level. If the F is transformed into half-metal, only the equal-spin triple pairs exist in the F layer, and the oscillation characteristic of critical current disappears. In addition, the FL and FR interfaces can work as conventional potential barriers. As a result, the critical current exhibits double oscillation behaviors with the increase of ferromagnetic thickness, in which the long-wave oscillation arises from the phase change of the spin-singlet pairs in the ferromagnetic layer, and the short-wave oscillation is caused by the resonant tunneling effect when the spin-singlet pairs and the equal-spin triplet pairs pass through two interfacial barriers.
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Keywords:
- Josephson junction /
- ferromagnet /
- spin-triplet pair /
- resonant tunneling
[1] Golubov A A, Kupriyanov M Y, Il’ichev E 2004 Rev. Mod. Phys. 76 411Google Scholar
[2] Buzdin A I 2005 Rev. Mod. Phys. 77 935Google Scholar
[3] Bergeret F S, Volkov A F, Efetov K B 2005 Rev. Mod. Phys. 77 1321Google Scholar
[4] Eschrig M 2011 Phys. Today 64 43Google Scholar
[5] Blamire M G, Robinson J W A 2014 J. Phys. Condens. Matter 26 453201Google Scholar
[6] Linder J, Robinson J W A 2015 Nat. Phys. 11 307Google Scholar
[7] Eschrig M 2015 Rep. Prog. Phys. 78 104501Google Scholar
[8] Mel'nikov A S, Mironov S V, Samokhvalov A V, Buzdin A I 2022 Physics-Uspekhi 65 1248Google Scholar
[9] Kimura T, Otani Y, Hamrle J 2006 Phys. Rev. Lett. 96 037201Google Scholar
[10] Keizer R S, Goennenwein S T B, Klapwijk T M, Miao G, Xiao G, Gupta A 2006 Nature 439 825Google Scholar
[11] Anwar M S, Czeschka F, Hesselberth M, Porcu M, Aarts J 2010 Phys. Rev. B 82 100501(RGoogle Scholar
[12] Kontos T, Aprili M, Lesueur J, Genêt F, Stephanidis B, Boursier R 2002 Phys. Rev. Lett. 89 137007Google Scholar
[13] Jiang J S, Davidović D, Reich D H, Chien C L 1995 Phys. Rev. Lett. 74 314Google Scholar
[14] Blum Y, Tsukernik A, Karpovski M, Palevski A 2002 Phys. Rev. Lett. 89 187004Google Scholar
[15] Ryazanov V V, Oboznov V A, Rusanov A Yu, Veretennikov A V, Golubov A A, Aarts J 2001 Phys. Rev. Lett. 86 2427Google Scholar
[16] Oboznov V A, Bol’ginov V V, Feofanov A K, Ryazanov V V, Buzdin A I 2006 Phys. Rev. Lett. 96 197003Google Scholar
[17] Yamashita T, Takahashi S, Maekawa S 2006 Appl. Phys. Lett. 88 132501Google Scholar
[18] Bergeret F S, Volkov A F, Efetov K B 2001 Phys. Rev. Lett. 86 4096Google Scholar
[19] Kadigrobov A, Shekhter R I, Jonson M 2001 Europhys. Lett. 54 394Google Scholar
[20] Eschrig M, Kopu J, Cuevas J C, Gerd Schön 2003 Phys. Rev. Lett. 90 137003Google Scholar
[21] Houzet M, Buzdin A I 2007 Phys. Rev. B 76 060504(RGoogle Scholar
[22] Asano Y, Tanaka Y, Golubov A A 2007 Phys. Rev. Lett. 98 107002Google Scholar
[23] Sosnin I, Cho H, Petrashov V T, Volkov A F 2006 Phys. Rev. Lett. 96 157002Google Scholar
[24] Robinson J W A, Witt J D S, Blamire M G 2010 Science 329 59Google Scholar
[25] Khaire T S, Khasawneh M A, Pratt W P, Birge N O 2010 Phys. Rev. Lett. 104 137002Google Scholar
[26] Klose C, Khaire T S, Wang Y X, et al. 2012 Phys. Rev. Lett. 108 127002Google Scholar
[27] Martinez W M, Pratt W P, Birge N O 2016 Phys. Rev. Lett. 116 077001Google Scholar
[28] Sanchez-Manzano D, Mesoraca S, Cuellar F A, et al. 2022 Nat. Mater. 21 188Google Scholar
[29] De Gennes P G 1966 Superconductivity of Metals and Alloys (New York: Benjamin) pp137–170
[30] Bagwell P F 1992 Phys. Rev. B 46 12573Google Scholar
[31] Beenakker C W J 1991 Phys. Rev. Lett. 67 3836Google Scholar
[32] Bardeen J, Kümmel R, Jacobs A E, Tewordt L 1969 Phys. Rev. 187 556Google Scholar
[33] Cayssol J, Montambaux G 2004 Phys. Rev. B 70 224520Google Scholar
[34] Bulaevskii L N, Buzdin A I, Kulić M L, Panyukov S V 1985 Adv. Phys. 34 175Google Scholar
[35] Meng H, Wu X Q, Ren Y J, Wu J S 2022 Phys. Rev. B 106 174502Google Scholar
[36] Markos P, Soukoulis C M 2008 Wave Propagation: From Electrons to Photonic Crystals and Left-Handed Materials (Princeton: Princeton University Press) pp56–73
[37] Cohen-Tannoudji C, Diu B, Laloë F 2019 Quantum Mechanics (Vol. 1) (Weinheim: Wiley-VCH) pp2–32
[38] Iogansen L V 1964 Sov. Phys.-JETP 18 146
[39] Meng H, Wu X Q, Zheng Z M 2013 Europhys. Lett. 104 37003Google Scholar
[40] Meng H, Wu J S, Wu X Q, Ren M Y, Ren Y J 2016 Sci. Rep. 6 21308Google Scholar
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图 1 (a) S/FL-F-FR/S结的结构示意图, 其中F内的粗箭头表示交换场方向, FL和FR为具有非共线磁矩的自旋活性界面; (b) Fj界面处磁矩
$ {{\boldsymbol{\rho}}}_{j} $ 的磁化方向, 其中$ {j}=\rm{L} $ ,$ \rm{R} $ 分别对应左侧和右侧界面.$ \theta_{j} $ 和$ \chi_{j} $ 分别表示Fj界面的极化角和方位角Figure 1. (a) Schematic diagram of the S/FL-F-FR/S junction, where thick arrow in F indicates the directions of the exchange field, and the FL and FR are spin-active interfaces with non-collinear magnetic moments; (b) the direction of magnetization
$ {{\boldsymbol{\rho}}}_{j} $ at the Fj interface, where$ {j}=\rm{L} $ and$ \rm{R} $ correspond to the left and right interfaces, respectively.$ \theta_{j} $ and$ \chi_{j} $ denote polar and azimuthal angles of the Fj interface, respectively图 2 S/F/S结中Josephson电流随铁磁特征的变化 (a)临界电流
$ I_{{\rm{c}}} $ 随铁磁交换场$ h_{z} $ 和铁磁厚度d的变化特征; (b)不同交换场下$ I_{{\rm{c}}} $ 随d的变化特征; (c)不同铁磁厚度时$ I_{{\rm{c}}} $ 随$ h_{z} $ 的变化特征;$ h_{z}/E_{{\rm{F}}} = 0.15 $ 时的(d)Andreev能谱$ E_{\rm{A}}(\phi) $ 和(e)电流-位相关系$ I(\phi) $ . 在所有图形中, 界面极化强度取$ P_{{\rm{L}}}=P_{{\rm{R}}} = 0 $ Figure 2. Variation of Josephson current with ferromagnetic characteristics in the S/F/S junction: (a) Critical current
$ I_{{\rm{c}}} $ versus exchange field$ h_z $ and ferromagnetic thickness d; (b) dependence of$ I_{{\rm{c}}} $ on d for different exchange fields; (c) dependence of$ I_{{\rm{c}}} $ on$ h_z $ for different ferromagnetic thicknesses; (d) Andreev energy spectrum$ E_{\rm{A}}(\phi) $ and (e) current-phase relation$ I(\phi) $ for$ h_{z}/E_{{\rm{F}}} = $ $ 0.15 $ . In all panels, the strengths of interfacial polarization are taken as$ P_{{\rm{L}}}=P_{{\rm{R}}} = 0 $ 图 3 临界电流
$ I_{\rm{c}} $ 随铁磁交换场$ h_z $ 和界面磁矩偏转角度差$ {\text{δ}}\chi $ 的变化特征 (a) kFd = 25; (b) kFd = 50; (c) kFd = 70. 在所有图形中, 界面极化强度取$ P_{{\rm{L}}}=P_{{\rm{R}}} = 1 $ Figure 3. The critical current
$ I_{{\rm{c}}} $ versus exchange field$ h_z $ and angle difference of interface magnetization rotation$ {\text{δ}}\chi $ : (a) kFd = 25; (b) kFd = 50; (c) kFd = 70. In all panels, the strengths of interfacial polarization are taken as$ P_{{\rm{L}}}=P_{{\rm{R}}} = 1 $ 图 4 临界电流
$ I_{\rm{c}} $ 随铁磁层厚度d和界面磁矩偏转角度差$ {\text{δ}}\chi $ 的变化特征 (a), (c), (e) 电流变化的侧视图; (b), (d), (f) 电流变化的俯视图. (a), (b)$ h_z/E_{{\rm{F}}} = 0.1 $ ; (c), (d)$ h_z/E_{{\rm{F}}} = 0.5 $ ; (e), (f)$ h_z/E_{\rm{F}} = 1.01 $ . 在所有图形中, 界面极化强度取$ P_{{\rm{L}}}=P_{{\rm{R}}} = 1 $ Figure 4. Variation of the critical current with ferromagnetic thickness d and angle difference of interface magnetization rotation
$ {\text{δ}}\chi $ : (a), (c), (e) Side view of current changes; (b), (d), (f) top view of current changes. (a), (b)$ h_z/E_{{\rm{F}}} = 0.1 $ ; (c), (d)$ h_z/E_{{\rm{F}}} = 0.5 $ ; (e), (f)$ h_z/E_{\rm{F}} = 1.01 $ . In all panels, the strengths of interfacial polarization are taken as$ P_{{\rm{L}}}=P_{{\rm{R}}} = 1 $ .图 5 (a)
$ {\text{δ}}\chi $ 取3个特殊值时临界电流$ I_{\rm{c}} $ 随铁磁层厚度d的变化特征; (b), (c)$ {\text{δ}}\chi = 0 $ 时的Andreev能谱$ E_{\rm{A}}(\phi)$ 和电流-位相关系$ I(\phi) $ (图(b)插图描述了$ I_{\rm{c }}$ 随$ {\text{δ}}\chi $ 的变化); (d), (e)$ k_{{\rm{F}}}d = 29.9 $ 时的Andreev能谱$ E_{\rm{A}}(\phi) $ 和电流-位相关系$ I(\phi) $ . 在所有图形中, 其他参数为$ h_{z}/E_{{\rm{F}}} = 0.1 $ 和$ P_{{\rm{L}}}=P_{{\rm{R}}} = 1 $ Figure 5. (a) Variation of the critical current with ferromagnetic thickness d when
$ {\text{δ}}\chi $ takes three special values; (b), (c) Andreev energy spectrum$ E_{\rm{A}}(\phi) $ and current-phase relation$ I(\phi) $ for$ {\text{δ}}\chi = 0 $ (the inset in panel (b) illustrates the dependence of$ I_{\rm{c}} $ on$ {\text{δ}}\chi $ ); (d), (e) Andreev energy spectrum$ E_{\rm{A}}(\phi) $ and current-phase relation$ I(\phi) $ for$ k_{{\rm{F}}}d = 29.9 $ . In all panels, other parameters are$ h_{z}/E_{{\rm{F}}} = 0.1 $ and$ P_{{\rm{L}}}=P_{{\rm{R}}} = 1 $ .图 6
$ {\text{δ}}\chi = 0 $ 时不同铁磁交换场下临界电流$ I_{\rm{c}} $ 随界面极化强度$ P_{{\rm{L}}} $ 和$ P_{{\rm{R}}} $ 的变化特征 (a)$ h_z/E_{{\rm{F}}} $ = 0.1; (b)$ h_z/E_{{\rm{F}}} $ = 0.5; (c)$ h_z/E_{{\rm{F}}} $ = 1.01. 所有图形中, F层厚度取$ k_{{\rm{F}}}d = 50 $ Figure 6. Variation of the critical current with the strengths of interfacial polarization
$ P_{{\rm{L}}} $ and$ P_{{\rm{R}}} $ for three different exchange fields in the case of$ {\text{δ}}\chi = 0 $ : (a)$ h_z/E_{{\rm{F}}} $ = 0.1; (b)$ h_z/E_{{\rm{F}}} $ = 0.5; (c)$ h_z/E_{{\mathrm{F}}} $ = 1.01. In all panels, the thickness of the F layer is taken as$ k_{{\rm{F}}}d = 50 $ -
[1] Golubov A A, Kupriyanov M Y, Il’ichev E 2004 Rev. Mod. Phys. 76 411Google Scholar
[2] Buzdin A I 2005 Rev. Mod. Phys. 77 935Google Scholar
[3] Bergeret F S, Volkov A F, Efetov K B 2005 Rev. Mod. Phys. 77 1321Google Scholar
[4] Eschrig M 2011 Phys. Today 64 43Google Scholar
[5] Blamire M G, Robinson J W A 2014 J. Phys. Condens. Matter 26 453201Google Scholar
[6] Linder J, Robinson J W A 2015 Nat. Phys. 11 307Google Scholar
[7] Eschrig M 2015 Rep. Prog. Phys. 78 104501Google Scholar
[8] Mel'nikov A S, Mironov S V, Samokhvalov A V, Buzdin A I 2022 Physics-Uspekhi 65 1248Google Scholar
[9] Kimura T, Otani Y, Hamrle J 2006 Phys. Rev. Lett. 96 037201Google Scholar
[10] Keizer R S, Goennenwein S T B, Klapwijk T M, Miao G, Xiao G, Gupta A 2006 Nature 439 825Google Scholar
[11] Anwar M S, Czeschka F, Hesselberth M, Porcu M, Aarts J 2010 Phys. Rev. B 82 100501(RGoogle Scholar
[12] Kontos T, Aprili M, Lesueur J, Genêt F, Stephanidis B, Boursier R 2002 Phys. Rev. Lett. 89 137007Google Scholar
[13] Jiang J S, Davidović D, Reich D H, Chien C L 1995 Phys. Rev. Lett. 74 314Google Scholar
[14] Blum Y, Tsukernik A, Karpovski M, Palevski A 2002 Phys. Rev. Lett. 89 187004Google Scholar
[15] Ryazanov V V, Oboznov V A, Rusanov A Yu, Veretennikov A V, Golubov A A, Aarts J 2001 Phys. Rev. Lett. 86 2427Google Scholar
[16] Oboznov V A, Bol’ginov V V, Feofanov A K, Ryazanov V V, Buzdin A I 2006 Phys. Rev. Lett. 96 197003Google Scholar
[17] Yamashita T, Takahashi S, Maekawa S 2006 Appl. Phys. Lett. 88 132501Google Scholar
[18] Bergeret F S, Volkov A F, Efetov K B 2001 Phys. Rev. Lett. 86 4096Google Scholar
[19] Kadigrobov A, Shekhter R I, Jonson M 2001 Europhys. Lett. 54 394Google Scholar
[20] Eschrig M, Kopu J, Cuevas J C, Gerd Schön 2003 Phys. Rev. Lett. 90 137003Google Scholar
[21] Houzet M, Buzdin A I 2007 Phys. Rev. B 76 060504(RGoogle Scholar
[22] Asano Y, Tanaka Y, Golubov A A 2007 Phys. Rev. Lett. 98 107002Google Scholar
[23] Sosnin I, Cho H, Petrashov V T, Volkov A F 2006 Phys. Rev. Lett. 96 157002Google Scholar
[24] Robinson J W A, Witt J D S, Blamire M G 2010 Science 329 59Google Scholar
[25] Khaire T S, Khasawneh M A, Pratt W P, Birge N O 2010 Phys. Rev. Lett. 104 137002Google Scholar
[26] Klose C, Khaire T S, Wang Y X, et al. 2012 Phys. Rev. Lett. 108 127002Google Scholar
[27] Martinez W M, Pratt W P, Birge N O 2016 Phys. Rev. Lett. 116 077001Google Scholar
[28] Sanchez-Manzano D, Mesoraca S, Cuellar F A, et al. 2022 Nat. Mater. 21 188Google Scholar
[29] De Gennes P G 1966 Superconductivity of Metals and Alloys (New York: Benjamin) pp137–170
[30] Bagwell P F 1992 Phys. Rev. B 46 12573Google Scholar
[31] Beenakker C W J 1991 Phys. Rev. Lett. 67 3836Google Scholar
[32] Bardeen J, Kümmel R, Jacobs A E, Tewordt L 1969 Phys. Rev. 187 556Google Scholar
[33] Cayssol J, Montambaux G 2004 Phys. Rev. B 70 224520Google Scholar
[34] Bulaevskii L N, Buzdin A I, Kulić M L, Panyukov S V 1985 Adv. Phys. 34 175Google Scholar
[35] Meng H, Wu X Q, Ren Y J, Wu J S 2022 Phys. Rev. B 106 174502Google Scholar
[36] Markos P, Soukoulis C M 2008 Wave Propagation: From Electrons to Photonic Crystals and Left-Handed Materials (Princeton: Princeton University Press) pp56–73
[37] Cohen-Tannoudji C, Diu B, Laloë F 2019 Quantum Mechanics (Vol. 1) (Weinheim: Wiley-VCH) pp2–32
[38] Iogansen L V 1964 Sov. Phys.-JETP 18 146
[39] Meng H, Wu X Q, Zheng Z M 2013 Europhys. Lett. 104 37003Google Scholar
[40] Meng H, Wu J S, Wu X Q, Ren M Y, Ren Y J 2016 Sci. Rep. 6 21308Google Scholar
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