Superconductor Spintronics - phy.pku.edu.cn
Transcript of Superconductor Spintronics - phy.pku.edu.cn
2
Review of last class
1. Antiferromagnetism and Exchange bias
2. Spin Seebeck effect in AFM
5. Anomalous Hall effect in AFM
3. AMR of AFM
6. Spin Hall effect in AFM
4. Switching of AFM
7. Spin current flow in AFM
7
Outline
1. Coupling between FM and SC
3. Spin Triplet pairs
4. Spin superconductor
5. Spin/magnon—SC cavity coupling
2. FM Josephson junctions
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Proximity effect vs. Andreev reflection
Proximity effect Andreev reflection
Coupling between FM and SC
13
Superconductor proximity effect
G. Miao, et al, Phys.Rev.Lett.101.137001(2008)
V (S)/ Fe (FM) tunneling junction
15C. Visani, et al, Nat. Phys. 10.1038 (2012)
YBa2Cu3O7 /La0.7Ca0.3MnO3SC/ half-metal:
Spin-triplet Andreev Reflection
16C. Visani, et al, Nat. Phys. 10.1038 (2012)
YBa2Cu3O7 /La0.7Ca0.3MnO3
@ T= 3K
SC/ half-metal:
Spin-triplet Andreev Reflection
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Spin-triplet Andreev Reflection
C. Visani, et al, Nat. Phys. 10.1038 (2012)
McMillan-Rowell resonance
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Superconductor spintronics
Long spin lifetime Large Spin Hall effect
Yang, et al, Nature Materials, 9 , 586–593 (2010)Wakamura, et al, Nature Materials, 14 , 675–678 (2015)
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� Josephson junction in weak FM
T. Kontos, et al, Phys. Rev. Lett. 89, 137007 (2002)
Q(E): Spectral current density
27
� Josephson junction in strong FMI c
RN(m
V)
dF(nm)
Robinson, Blamire, et al, PRL 97, 177003 (2006)
Nb /Co /Nb
Nb /Py /Nb
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S F
Bergeret, Volkov & Efetov, PRL 90, 117006 (2003)
Spin-triplet supercurrent
Long-range transport of spin-triplet in FM
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Spin-triple supercurrent
Kerizer, et al, Nature 439, 825 (2006)
0.3 -1 um
Half-Metallic Josephson junction
35
Half-Metallic Josephson junction
Kerizer, et al, Nature 439, 825 (2006)
Spin-triplet supercurrent
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Spin-triplet supercurrent
Kerizer, et al, Nature 439, 825 (2006)
Half-Metallic Josephson junction
37Teun Klapwijk, Nature Physics 6, 329 (2010)
Spin singlet to triplet conversion
Spin-triplet supercurrent
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Spin triplet Josephson junction
X = Co
X = PdNi (4nm)
Cooper pairs feel noncollinear M between X and Co layers
Khaire, Khasawneh, Pratt, & Birge, Phys. Rev. Lett. 104, 137002 (2010)
Spin singlet to triplet conversion
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Spin triplet Josephson junction
W.A. Robinson, et al, Science 329 (5987), 59-61 (2010)
Spin singlet to triplet conversion
40W.A. Robinson, et al, Science 329 (5987), 59-61 (2010)
Spin singlet to triplet conversion
Spin triplet Josephson junction
41Eschrig, Physics Today, 64, 43 (2011)
Spin singlet to triplet conversion
Spin triplet Josephson junction
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Spin pumping into Superconductor
K.R. Jeon, et al, Nat. Mater. 17, 499–503(2018)
Non-equilibrium spin-triplet supercurrent
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Spin pumping into Superconductor
K.R. Jeon, et al, Nat. Mater. 17, 499–503(2018)
Non-equilibrium spin-triplet supercurrent
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Spin pumping into Superconductor
Non-equilibrium spin-triplet supercurrent
K.R. Jeon, et al, Nat. Mater. 17, 499–503(2018)
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Charge superconductivity: Zero resistance
Spin superfluidity:Zero spin resistance
Sp
in S
ign
al
T (K)
Q. Sun and X. C. Xie, PRB 84, 214501 (2011), PRB 86, 085441 (2012), Nature Comm. 4, 2951(2013)
Spin superfluidity
Spin superfluidity: Spin analogue of superconductivity
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Charge superconductivity: Meissner effect (B)
Spin superfluidity:Meissner effect (E)
Q. Sun and X. C. Xie, PRB 84, 214501 (2011), PRB 86, 085441 (2012)
Spin superfluidity: Spin analogue of superconductivity
Spin superfluidity
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Charge superconductivity: Josephson effect
Spin superfluidity:Spin-Josephson effect
Sun and Xie, PRB 84, 214501(2011), PRB 86, 085441(2012)Liu, et al, PRB (2014)Chen, Kent, MacDonald, PRB 90, 220401(R) (2014).
Spin superfluidity
Spin superfluidity: Spin analogue of superconductivity
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Charge superconductivity: Spin superfluidity:
ie, Wang, et al, Science (2011)
e-h BECCharge: 0Spin pairs: (1/2 + 1/2)
Magnon BECCharge: 0Magnon: Spin-1
Sonin, JETP 74,2079-2111(1978)Q. Sun and X. C. Xie, PRB (2011), PRB (2012), Nature Comm. (2014)S.Takei, et al, PRB 90, 094408 (2014)
Spin superfluidity: Spin analogue of superconductivity
Spin superfluidity
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Spin Superfluidity Materials
1) He-3
Spin-polarized
Book:Superfluidity and superconductivity (David R. Tilley, John Tilley)
S = 1⁄2
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Spin Superfluidity Materials
Borovik-Romanov, et al, JETP Lett. 45, 124 (1987)Review: Sonin, Advances in Physics (2010)
Spin polarized He3 Superfluid spin “Current”
1) He-3
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Spin Superfluidity Materials
1) He-3
A. S. Borovik-Romanov, et al, JETP Lett. 45, 124 (1987)
Phase slippage
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Spin Superfluidity Materials
Borovik-Romanov, et al, JETP Lett. 45, 124 (1987)Review: Sonin, Advances in Physics (2010)
Solid State Materials?
Spin polarized He3 Superfluid spin “Current”
1) He-3
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Spin Superfluidity Materials
2)Magnon in Ferromagnetic materials
FM
Magnon (Charge 0, Spin-1 boson)
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Spin Superfluidity Materials
2)Magnon BEC
Magnon BEC by parametric pumping
S. O. Demokritov, et al, Nature 443, 430 (2006)D. A. Bozhko, et al, Nat. Phys. 12, 1057 (2016)
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Spin Superfluidity Materials
2)Magnon BEC
S. O. Demokritov, et al, Nature 443, 430 (2006)D. A. Bozhko, et al, Nat. Phys. 12, 1057 (2016)
Magnons flow between two Magnon BECs Spin superfluidity (< ~ 1 Micro second)
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Spin Superfluidity Materials
3) Spin superfluidity in AFM (FM graphene)
e-h BECCharge: 0Spin pairs: (1/2 + 1/2)
Q. Sun and X. C. Xie, PRB 87, 245427 (2013)Takei, et al, PRL 116, 216801(2016)Q. Sun and X. C. Xie, PRB 84, 214501(2011)
v = 0 quantum state of graphene
Novoselov et al., Nature 438, 197–200 (2005)Zhang et al., Nature 438, 201–204 (2005)
Proximity-induce FM graphene
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Spin Superfluidity Materials
3) Spin superfluidity in canted AFM (insulator)
Magnon Charge: 0Magnon: Spin-1 boson
Takei, et al, PRB 90, 094408 (2014)
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Spin Superfluidity Materials
AFM Phase in v = 0 graphene
A.F. Young, et al, Nature 505, 528–532 (2014)
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Spin Superfluidity Materials
Spin current as a probe of spin superfluidity
Takei, et al, PRB 90, 094408 (2014)Takei, et al, PRL 115, 156604 (2015)
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[0001]
O
Cr
Cr2O3 AFM insulator
Al2O3
Cr2O3
500 nm
1 nm
-1 nm
1 nm
-1 nm
500 nm
Atomic flat (0001)-Cr2O3 AFM films
~ 19 nm
(0001)-oriented Cr2O3
Pulsed Laser deposition
Spin Superfluidity in canted AFM
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Pt Pt
Cr2O3
x
y
z
B
S1
S2
mx
Nonlocal spin transport
Field induced Canted AFM
0 60 120 180 240 300 360
-0.4
-0.2
0.0
0.2
0.4 R
2
sin ()
R2w
(V/A
2)
φ (degree)
d = 10 µm
Js Mφ
B
.VNL
..I
Thermal spin injection
Spin current detector (ISHE)
RNL detects spin conductance
Nonlocal technique previously developed to study Magnon diffusion in ferromagnetic insulator YIG:Cornelissen, et al, Nat. Phys. 11,1022–1026(2015)
Spin Superfluidity in canted AFM
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Saturation of the nonlocal spin signal
Saturation of the nonlocal spin signal (spin conductance )
Spin superfluidity in canted AFM
Spin Superfluidity in canted AFM
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Slow decay:
Lα related to the damping of AFM
Takei, et al, PRB 90, 094408 (2014)Sonin, Private communications (2018)
���~��
� + ��
Long distance spin transport
Spin Superfluidity in canted AFM
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Fast decay (magnon diffusion): Slow decay:
Lα related to the damping of AFM
Takei, et al, PRB 90, 094408(2014)
Similar to incoherent magnons in YIG:Cornelissen, et al, Nat. Phys.11,1022–1026 (2015)
���~exp(� �⁄ )
1 − exp(2 � �⁄ )
���~��
� + ��
Comparison with incoherent magnons
Spin Superfluidity in canted AFM
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Critical current density
A critical spin current (IS) density is needs to overcome AFM pinning (anisotropy)
Spin Superfluidity in canted AFM
Pt Pt
Cr2O3
x
y
z
0.0 2.5x10-7 5.0x10-7
0
10n
20n
30n
40n
50n
V2w
NL (
V)
I2inject (A2)
T=2K T=5K
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Saturation of the nonlocal spin signal at LT
Long distance spin transport (length dependence)
Critical current for spin superfluidity
Phase diagram of field-induced canting
Pt Pt
Cr2O3
W. Yuan, Q. Zhu, T. Su, Y. Yao, W. Xing, Y. Chen, Y. Ma, X. Lin, J. Shi*, R.Shindou, X. C. Xie*, and Wei Han*, Science Advances, 4: eaat1098 (2018)
Spin Superfluidity in canted AFM
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Spin Superfluidity in canted AFM
Fe2O3
Incoherent magnon Lebrun and Klaui, et al, Nature 561, 222–225 (2018)
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Spin Superfluidity in canted AFM
(11-20) oriented Fe2O3 on Al2O3
32 34 36 38 40 42
Al2O3 (11-20)
Inte
nsity
2Theta (Degree)
Fe2O3 (11-20)
0 50 100 150 200 250
0.00
0.04
0.08
0.12
0.16
R
NL
(V/A
2)
T (K)
Incoherent magnon
Fe2O3
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Spin Superfluidity in canted AFM
Fe2O3
1 2 3 4 5
0.1RN
L(V
/A2)
L (mm)
���~exp(� �⁄ )
1 − exp(2 � �⁄ )
W. Xing, Y. Ma, et al, unpublished
T = 150 K
0.0 5.0x10-7
1.0x10-6
0.00
0.05
0.10
IAC2 (A2)
V2w
(mV
)
T = 150 K
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Spin Superfluidity in canted AFM
W. Xing, L. Qiu, X. Wang, Y. Yao, Y. Ma, R. Cai, S. Jia, X. C. Xie, and Wei Han*, Physical Review X 9, 011026 (2019)
10 μm
10 μm
0 2 4 6 8 10 12 14 16
0.1
1
���~exp(� �⁄ )
1 − exp(2 � �⁄ )
���~exp(� �⁄ )
1 − exp(2 � �⁄ )
13 nm
24 nm
0 2 4 6 8 10 120.01
0.1
1
10
79Takei, et al, PRL 115, 156604 (2015)Petr Stepanov, et al, Nature Physics 14, 907–911(2018)
Spin Superfluidity in quantum AFM
Quantum AFM Phase in v = 0 graphene
80Petr Stepanov, et al, Nature Physics 14, 907–911(2018)
Spin Superfluidity in quantum AFM
Quantum AFM Phase in v = 0 graphene
81Petr Stepanov, et al, Nature Physics 14, 907–911(2018)
Saturation of nonlocal signal
Spin Superfluidity in quantum AFM
Quantum AFM Phase in v = 0 graphene
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Spin superfluidity
Magnon BEC(< 1 μs)
Solid State Materials
Pt Pt
Cr2O3
Canted AFM Cr2O3
Graphene (ν = 0)
Spin Superfluidity
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Spin superfluidity
Magnon BEC(< 1 μs)
Solid State Materials
Pt Pt
Cr2O3
Canted AFM Cr2O3
Graphene (ν = 0)
Spin Superfluidity
The Rise of Spin Superfluidity!
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SC Qubit - magnon coupling
Y. Tabuchi, et al, Science 329, 405–408 (2015)
Kittel mode
Cavity mode
Cavity spintronics
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Cavity Spintronics Gets More with Less
Can-Ming Hu, Physics 12, 97 (2019)
silicon substrate
microwave cavity
magnetic stripe
Cavity spintronics
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Nb superconducting resonator
Cavity spintronics
Justin T. Hou and Luqiao Liu, Phys Rev Lett.123.107702 (2019)
93Justin T. Hou and Luqiao Liu, Phys Rev Lett.123.107702 (2019)
Strong magnons and photons coupling
Cavity spintronics
95
Summary
1. Coupling between FM and SC
3. Spin Triplet pairs
4. Spin superconductor
5. Spin/magnon—SC cavity coupling
2. FM Josephson junctions