Conversion between spin and charge currents by Rashba or ...people.ece.umn.edu/groups/cspin/events/tsd2016/... · Conversion between spin and charge currents by Rashba or Topological

Conversion between spin and charge currents

by Rashba or Topological Insulator interfaces

and perspective for low power spintronic devices

1) Introduction to spin-orbitronics.

2) Conversion between charge and spin current with Rashba or TI Interfaces.

3) Potential of TI for applications

A. Barhélémy, M. Bibes, A. Fert, J-M. George, H.Jaffres, E. Lesne, N. Reyren,

J-C Rojas-Sánchez, CNRS/Thales, Palaiseau, France

L. Vila, J.-P. Attané, G. Desfond, Y. Fu, S. Gambarelli, M. Jamet, A. Marty, S.

Oyarzun,. L. Vila, CEA Grenoble, France

J.M. De Teresa, Un. Zaragoza, Y. Ohtsubo, Osaka University

P. LeFevre, F. Bertran, A. Taleb, SOLEIL Synchrotron, Gif, France

C.Rinaldi, R.Bertacco, Poli.Milan, R.Calarco, R.Wang,Drude Inst. Berlin

TI DEVICES, May 12-13 2016, A. Fert, UMR CNRS/Thales and Univ. Paris-Sud,

Conversion between spin and charge currents

by Rashba or Topological Insulator interfaces at Room Temp.

and perspective for low power spintronic devices

1) Introduction to spin-orbitronics.

2) Conversion between charge and spin current with Rashba or TI Interfaces.

3) Potential of TI for applications

A. Barhélémy, M. Bibes, A. Fert, J-M. George, H.Jaffres, E. Lesne, N. Reyren,

J-C Rojas-Sánchez, CNRS/Thales, Palaiseau, France


Oyarzun,. L. Vila, CEA Grenoble, France

J.M. De Teresa, Un. Zaragoza, Y. Ohtsubo, Osaka University

P. LeFevre, F. Bertran, A. Taleb, SOLEIL Synchrotron, Gif, France

C.Rinaldi, R.Bertacco, Poli.Milan, R.Calarco, R.Wang,Drude Inst. Berlin

TI DEVICES, May 12-13 2016, A. Fert, UMR CNRS/Thales and Univ. Paris-Sud,

5 MA/cm2

Interface- induced

skyrmions and

chiral domain walls

Spin Hall effect

Edelstein-type effects at

Rashba and topological

insulator interfaces

Graphene

+ spin-orbit

Spin-orbitronics

Oxide

interfaces

2D

2D

2D

Motion of skyrmion

motion by SHE

2D

3D

JS = vertical spin current injected

into an adjacent layer by SHE

CJ Js

M

jc

w σ

Switching of nanomagnet by the spin

current JS injected by the SHE in an adjacent SO layer

Bulk materials

3D charge current → 3D spin current conversion by Spin Hall Effect (SHE)

and 3D spin current → 3D charge current by Inverse SHE (ISHE)

Yield of conversion between charge and spin current

JS = vertical spin current injected

into an adjacent layer by SHE

CJ

3-terminal SOT-MRAM

Js

M

jc

w σ

Switching of nanomagnet by the spin

current JS injected by the SHE in an adjacent SO layer

Bulk materials

3D charge current → 3D spin current conversion by Spin Hall Effect (SHE)

and 3D spin current → 3D charge current by Inverse SHE (ISHE)

M.Cubukcu et al., APL 2015 : switching in 0.4ns current pulse ≃ 108 Amp/cm2 in 1kOe

Z. Wang, W. S. Zhao et al., J. Phys. D 2015 : STT + SOT < 1ns, zero field, current densities ≃ 107 Amp/cm2

Spin/charge conversion by Rashba interfaces and topological insulators

BiAg

ez

αR = Rashba

coefficient(example at the

Bi/Ag interface

2DEG)

ez

Rashba interface

kx ky

kx ky

E(k)

kx

ky

E(k)

Topological insulator

kx ky

Spin/charge conversion by Rashba interfaces and topological insulators

BiAg

ez

αR = Rashba

coefficient(example at the

Bi/Ag interface

2DEG)

ez

Rashba interface

kx ky

kx ky

E(k)

kx

ky

E(k)

Topological insulator

kx (nm-1)-2 -1 0 1 2

E(e

V)

0

-0.2

-0.4

kx (nm-1)-1 0 1

E (

eV

)

0

-0.2

-0.4

kx ky

Edelstein (EE) and Inverse Edelstein Effect (IEE)

Charge

Current jC

Edelstein Effect

Rashba interface Topological insulator

k charge current

jC in 2DEG

induces nonzero spin

density y

overpopulateddepleted

k

depleted

overpopulated

k

Charge

Current jC

Edelstein Effect


k

Inverse Edelstein Effect

charge current

jC in 2DEG


density y


injection

k

extractioninjection

k

extraction


jCSpin

pumping

Injection of

spin current jS

induces charge

current jC

jS

k

Charge

Current jC

Edelstein Effect


k


charge current

jC in 2DEG


density y


RIEE

DsIEE

Dc

with

jj

32

A/m A/m2

length

injection

k

extractioninjection

k

jS

extraction


Rojas-Sanchez, AF et al, Nat.Com. 013, Shen et al, PRL014

Injection of

spin current jS

induces charge

current jC

jC

k

Charge

Current jC

Edelstein Effect


k


charge current

jC in 2DEG


density y


RIEE

D

sIEE

D

c

with

jj

32

A/m A/m2

length

FIEE

D

sIEE

D

c

vwith

jj

32

A/m A/m2

length

injection

k

extractioninjection

k

jC

extraction


Rojas-Sanchez et al, PRL 116, 096602 (2016), Culcer, Physica012

Injection of

spin current jS

induces charge

current jC

jC

jS

k

Charge

Current jC

Edelstein Effect


k


charge current

jC in 2DEG


density y


RIEE

D

sIEE

D

c

with

jj

32

A/m A/m2

length

FIEE

D

sIEE

D

c

vwith

jj

32

A/m A/m2

length

injectionextraction

α-GeTe (Dil et al)

k

extractioninjection

k


Injection of

spin current jS

induces charge

current jC

Rojas-Sanchez et al, PRL 116, 096602 (2016), Culcer, Physica012

- Bi/Ag interface* (J-C. Rojas-

Sanchez, AF et al, Nature

Communications, 4, 2944, 2013)

- Other examples presented today:

- topological 2DEG: α-Sn and

LAO/STO interface

°.°.°.°.Bi

Ag

V

3D spin current js injected by spin

pumping (FerroMagneticResonance)

Agjs

2D charge current

derived from V

Inverse Edelstein effect (IEE) in spin pumping experiments

* Before Bi/Ag, first observed

in n-GaAs-AlGaAs QW,

Ganichev et al, Nature 417,

153, 2002

Ag/Bi interface

JS

IC

M(t)

NiFe (t = 15nm)

Bi (t = 8nm)

9.5 GHzAg (t = 0, 5,10 or 20nm)

V

l

a

l =1, 1.5, 2.4 or 3 mm

a =0.4 mm, c

0.10 0.12 0.14

H (T)0.10 0.12 0.14

H (T)

NiFe(15)/Bi(8)//

0.08 0.10 0.120.0

0.4

I (

A)

H (T)

dX

''/dH

(a. u.) NiFe(15)/Ag(10)// NiFe(15)/Bi(8)/Ag(5)//

ba

0cI

Agonly

NiFe(15)/Ag(5)/Bi(8)//

I c(μ

A)

smalliscI

BionlycI

AgBi

large

interface/

large

AgBia

istherewhenonly

islR

VcI

J-C. Rojas-Sanchez, AF et al, Nature Communications, 4, 2944, 2013

Room temperature

Spin to charge conversion by Bi/Ag Rashba interfaces

Ag/Bi interface

JS

IC

M(t)

NiFe (t = 15nm)

Bi (t = 8nm)

9.5 GHzAg (t = 0, 5,10 or 20nm)

V

l

a

l =1, 1.5, 2.4 or 3 mm

a =0.4 mm, c

0.10 0.12 0.14

H (T)0.10 0.12 0.14

H (T)

NiFe(15)/Bi(8)//

0.08 0.10 0.120.0

0.4

I (

A)

H (T)

dX

''/dH

(a. u.) NiFe(15)/Ag(10)// NiFe(15)/Bi(8)/Ag(5)//

ba

0cI

Agonly

NiFe(15)/Ag(5)/Bi(8)//

I c(μ

A)

smalliscI

BionlycI

AgBi

large

interface/

large

AgBia

istherewhenonly

islR

VcI

J-C. Rojas-Sanchez, AF et al, Nature Communications, 4, 2944, 2013

Room temperature

Spin to charge conversion by Bi/Ag Rashba interfaces

S. Sangiao et al. APL 106, 172403 (2015)

as expected by Rashba symmetry,

Ic has opposite signs for, respectively,

Ag above Bi and Ag under Bi

Ag

Bi

IS Bi

Ag

IS

Ic Ic

injectionextraction

RAgBi

IEE

s

c

j

j /

J-C. Rojas-Sánchez et al.

Nature Comm. 2013

(Similar results by K. Shen,

R. Raimondi et al, PRL. 2014)

)/( mA

)2/( mA

0 5 10 15 200.0

0.2

0.4

IR

EE (n

m)

tAg (nm)0 5 10 15 20

0.0

0.2

0.4

IR

EE (n

m)

tAg (nm)

Other results on Bi/Ag: Nomura et al, APL 2015

nmAgBi

IEE3.02.0

/

k

-k

injectionextraction

RAgBi

IEEDsj

Dcj

/

3

2 J-C. Rojas-Sánchez et al.

Nature Comm. 2013

(Similar results by K. Shen,

R. Raimondi et al, PRL. 2014)

)/( mA

)2/( mA

0 5 10 15 200.0

0.2

0.4

IR

EE (n

m)

tAg (nm)0 5 10 15 20

0.0

0.2

0.4

IR

EE (n

m)

tAg (nm)

More recent results on Bi/Ag, Sb/Ag..

W. Zhang et al. JAP 117, 17C727 (2015)

λIEE(Ag/Bi) ~ 0.1nm >IλIEE(Ag/Sb) ~0.03 nm 0.1nm

Sisasa et al, 2015, λIEE(Cu/Bi) derived from LSV is small and its sign changes with T

nmAgBi

IEE3.02.0

/

Spin to charge current conversion at Ag/IrO2

(Fujiwara, Otani et al, Nat Comm. 2013,DOI: 10.1038/ncomms3893)and Cu/Bi2O3 interfaces (Karube, Otani et al, App.Phys. Expr. 9,033001)

Zhang et al (PRL 2015), Jungfleisch et al (ArXiv 1500.0141): measurement of charge to spin conversion (direct EE) at Bi/Ag interface

k

-k

ARPES: Y. Ohtsubo et al.

PRL 11, 216401 (2013)

InSb//-Sn(24-30ML)

F = 7.3 105 m/s (4.8 evÅ)

Casiopee beam line at SOLEIL, Room temperature

PRL 111, 216401 (2013)

Our -Sn/Fe and -Sn/Ag/Fe samples

(-Sn:30ML) have been grown in the same conditions in situ on the samebeam line to check by ARPES if the

topological states are or are not keptafter depositing Fe or Ag for our spin

pumping experiments

Dirac-cone with helical spin polarization

Spin to charge conversion by Dirac cone states with helical spin polarization of -Sn

24 ML

DFT 44ML

First stage : ARPES in -Sn(30ML) + Fe or Sn(30ML)+Ag

Sn

Sn + 1.8 Å Fe

Sn + 0.9 Å Fe

Room temperature Rojas-Sanchez et al, PRL 116, 096602 (2016)

The Dirac cone remains when

adding Ag on Sn

IEE expected in spin pumping from Fe into

Ag/Sn bilayers

Sn

Sn + 1.8 Å Fe

Sn + 0.9 Å Fe Sn + 4.3 Å Ag

Sn + 12 Å Ag

Sn

Room temperature

First stage : ARPES in -Sn(30ML) + Fe or Sn(30ML)+Ag

Rojas-Sanchez et al, PRL 116, 096602 (2016)

Spin pumping on -Sn/Fe and -Sn/Ag(2nm)/Fe

H||[100]

InSb//Sn(24ML)/Ag(2nm)/Fe(5nm)/Au(3nm)

24 ML

2 nm

5 nm

2 nm

strong spin absorption by pumping Fe on Ag/Sn , weak spin absorption by pumping directly from Fe

an Sn

//Sn/Ag/Fe: = 0.028

//Fe: = 0.0062

//Sn/Fe: = 008

Rojas-Sanchez et al, PRL 116, 096602 (2016)



24 ML

2 nm

5 nm

2 nm

0.05 0.10 0.15

0

2

4

(

A)

H (T)

hrf= 1.0 G

P = 200 mW

dX

''/d

H (

arb

. u

nits)

f = 9.6732 GHz

0.05 0.10 0.15

H (T)

hrf= 1.0 G

P = 200 mW

f = 9.78 GHz

0.05 0.10 0.15

H (T)

hrf= 1.0 G

P = 200 mW

f = 9.684 GHz

//Fe/ //Sn/Fe/ //Sn/Ag/Fe/

nm

vj

j

Sn

IEE

F

TI

IEE

s

c

1.2

)/( mA

)2/( mA

Room temperature

Rojas-Sanchez et al,

PRL 116, 096602 (2016)

Precession angle ≃ 10-2



24 ML

2 nm

5 nm

2 nm

0.05 0.10 0.15

0

2

4

(

A)

H (T)

hrf= 1.0 G

P = 200 mW

dX

''/d

H (

arb

. u

nits)

f = 9.6732 GHz

0.05 0.10 0.15

H (T)

hrf= 1.0 G

P = 200 mW

f = 9.78 GHz

0.05 0.10 0.15

H (T)

hrf= 1.0 G

P = 200 mW

f = 9.684 GHz


nm

vj

j

Sn

IEE

F

TI

IEE

s

c

1.2

)/( mA

)2/( mA

Room temperature


PRL 116, 096602 (2016)




24 ML

2 nm

5 nm

2 nm

0.05 0.10 0.15

0

2

4

(

A)

H (T)

hrf= 1.0 G

P = 200 mW

dX

''/d

H (

arb

. u

nits)

f = 9.6732 GHz

0.05 0.10 0.15

H (T)

hrf= 1.0 G

P = 200 mW

f = 9.78 GHz

0.05 0.10 0.15

H (T)

hrf= 1.0 G

P = 200 mW

f = 9.684 GHz


nm

vj

j

Sn

IEE

F

TI

IEE

s

c

1.2

)/( mA

)2/( mA

Room temperature

λIEE >0 in agreement

with CCW chirality in

upper cone (from spin-

resolved ARPES)


PRL 116, 096602 (2016) Precession angle ≃ 10-2



24 ML

2 nm

5 nm

2 nm

0.05 0.10 0.15

0

2

4

(

A)

H (T)

hrf= 1.0 G

P = 200 mW

dX

''/d

H (

arb

. u

nits)

f = 9.6732 GHz

0.05 0.10 0.15

H (T)

hrf= 1.0 G

P = 200 mW

f = 9.78 GHz

0.05 0.10 0.15

H (T)

hrf= 1.0 G

P = 200 mW

f = 9.684 GHz


nm

vj

j

Sn

IEE

F

TI

IEE

s

c

1.2

)/( mA

)2/( mA

Room temperature

In progress, dependence

on T, -Sn thickness, gate

voltage, applied field +

inverse conversion

Other spin/charge conversions

with TI,

e.g Shiomi et al, PRL014,

Jamali et al NanoLetters 015

(spin pumping),

Tang et al, Nano Letters 014,

(electrical spin inject. )


Relaxation time τ of out-of-equilibrium distribution in topological states

Dots correspond to maximum intensity in E=cst scansRojas-Sanchez et al,

PRL 116, 096602 (2016)

)/6106.0(

23.0/

/61056.0

Snfreeforsm

nmAgwithSnAgatconefor

smFv

)5:/(7.3

/61056.0,1.2

fsAgBifs

smFvnmFvIEE

For circular contours

ARPES along 110

Relaxation time τ of out-of-equilibrium distribution in topological states

Dots correspond to maximum intensity in E=cst scansRojas-Sanchez et al,

PRL 116, 096602 (2016)

)5:/(7.3

/61056.0,1.2

fsAgBifs

smFvnmFvIEE

For circular contours

ARPES

intensity

mapping

in (kx, ky) plane

(low resolution)

ARPES along

110 (high

resolution)

kxky

kx ky

1) Ulta-fast time-resolved

ARPES (ex:Bi2.2Te3 Hajlaoui

et al, Nat. Comm. 2013)

τ in the ps range

(ballistic length in the μm

range)

Relaxation time τ of out of equilibrium states in Rashba or TI 2DEGs

τ = τinternal

2) Spin pumping

τ in the fs range*

(ballistic lenght in

the nm range)

Additional relaxation of the

spin+momentum accumulation

by spin-flip scattering

from 2D states to 3D metal

Additional relaxation by

spin-flip scattering

from 2DEG to metal

IEE (or EE) would more

efficient (λIEE longer)

without proximity of the

Rashba or TI states with a

metal, i.e with interface with

an insulating ferromagnet

(YIG, etc) or a tunnel

interface

LAO/STO system : large Ic production and gate effect

IEE up to 6.4 nm ( definitely higher than with α-Sn and at Bi/Ag interfaces )

90 100-25

0

25

50

75

90 100 90 100 90 100 90 100 90 100 90 100

I2D

C (

mA

/m)

T = 7K

+100 V+50 V0 V-50 V-100 V-120 V

H (mT)

-140 V

Cylindrical cavity(INAC/CEA-Grenoble)allow for measurements down to few Kelvins, combined with voltage/current probe.

T = 7 K

1uc

1-4 u.c. LaAlO3

SrTiO3

E. Lesne, Ph.D. Thesis,

CNRS/Thales lab.

Lifshitz pointn1.8 1013 cm-2

R max

kx

E

dxy

dxz/yz

dxy

dxz/yz

VG<0

VG>0

1) Charge to spin conversion: SHE already used in SOT-RAMS, Rashba and TI

already proposed by INTEL, advantage of TI for spin-orbic logic (Manipatruni et al)

Ex: 3-terminal SOT MRAMZ. Wang, W. S. Zhao et al., Journal of Physics: D (2015)

Perspective for exploiting the conversion between spin and

charge by TI in low-power spintronic devices (Room Temp.),

assessment of the advantage of TI

Manipatruni et al, ArXiv (Intel)

Bi

Ag

Conversion with Bi/Ag

2) Perspective for spin to charge conversion with TI,

first exemple: spin battery,




2) Perspective for spin to charge conversion with TI,

second exemple: conversion of heat flow into electrical power




Vert

ical

heat

flo

w

Inverse spin Hall effect (ISHE) vs inverse Edelstein effect (IEE) WITH

Spin-to-charge conversion by « bulk » spin-orbit effect through inverse spin hall effect (ISHE)

Spin-to-charge conversion achieved through inverse (Rashba-) Edelstein effect (IEE)

3D layers Interfaces and 2DEGs

3DsJ

3DsJ

2DEG 2DcJ

2DcJ t

DsSHE

Dc jjISHE 33:

sfSHEIEE

sfD

ssfSHED

c

DssfsfSHE

Dc

Dc

leffectiveanmosttheatwith

EffectEdelsteinInverseantoscorrespondwhich

ltforjlJmaximumitsreaches

jltthldzjJISHE

*

32

332

,,

)2/(:

DsIEE

Dc jjIEE 32:

)/( mA )2/( mA)2/( mA)2/( mA

Inverse spin Hall effect (ISHE) vs inverse Edelstein effect (IEE) WITH

Spin-to-charge conversion by « bulk » spin-orbit effect through inverse spin hall effect (ISHE)

Spin-to-charge conversion achieved through inverse (Rashba-) Edelstein effect (IEE)

3D layers Interfaces and 2DEGs

3DsJ

3DsJ

2DEG 2DcJ

2DcJ t

DsSHE

Dc jjISHE 33:

sfSHEIEE

sfD

ssfSHED

c

DssfsfSHE

Dc

Dc

leffectiveanmosttheatwith

EffectEdelsteinInverseantoscorrespondwhich

ltforjlJmaximumitsreaches

jltthldzjJISHE

*

32

332

,,

)2/(:

DsIEE

Dc jjIEE 32:

)/( mA )2/( mA)2/( mA)2/( mA

Maximum charge current inducedby ISHE characterized by the effective conversion length

λ*SHE=ѲSHElsfto be compared to

λIEEfrom ISHE to IEE the gain in

current is at least λIEE/ λ*SHE

Compared spin to charge conversion yield of TI (α-Sn) and ISHE (Pt and W)

1) Gain in charge current JC for the same injected spin current density jS from

SHE in Pt or W (for t >> lsf ) to α-Sn (taken as an example of TI, λ=2.1nm)

- Gain from Pt (θSHE= 0.056*, lsf = 3.4nm*) to α-Sn: JC(α-Sn)/JC(Pt) =11.03

(Pt would be as efficient as α-Sn if its SH-angle was 62%instead of 5.6%)

- Gain from W(θSHE = 0.33**,lsf = 1.4nm***) to α-Sn: JC(α-Sn)/ JC(W) = 4.5

or from W with θSHE = 0.19***,lsf = 1.4nm*** to α-Sn: JC(α-Sn)/ JC(Pt) = 7.9

(W would be as efficient as α-Sn if its SH-angle was 150% instead of 19-33%)

*from C.Rojas-Sanchez et al,PRL112, 2014

** from Pai et al, APL 101, 2012

*** from Kim et al, arXiv:150308903 2

Compared spin to charge conversion yield of TI (α-Sn) and ISHE (Pt and W)

2) Gain in electrical power PC for the same injected spin current density ,

with PC= R⎕ JC2

Optimal condition: R⎕ ≃4kΩ for α-Sn surface 2DEG between insulating

materials

and R⎕ = ρ/t for the SHE metal layer (Pt, W) of optimal t = lsf )

- Gain from Pt (θSHE= 0.056, lsf = 3.4nm, resistivity = 17 μΩcm) to α-Sn

PC(α-Sn)/ PC(Pt) ~ 104

-Gain from W (θSHE = 0.19-33, lsf = 1.4nm, resistivity =160 μΩcm) ) to α-Sn

PC(α-Sn)/ PC(W) ~ 103

Compared charge to spin (or charge to

torque) conversion yields between

1) TI (Bi1-xSbx)Te3

with conversion factor jS/JC ≡ qICS ≃ 1nm-1

(Kondou et al, ArXiv:1510.03572) and

2) SHE-Pt or - W layers with jS/JC = ѲSHE /lsf in the optimal conditions t = lsf

1) Gain in ejected 3D spin current density JS

for the same 2D charge current density jC in metal layer or 2D topological states

between SHE with Pt or W (for t ≃ lsf ) and (Bi1-xSbx)Te3 (qICS ≃ 1nm-1 )

- Gain from Pt (θSHE = 0.056, lsf = 3.4nm) to α-Sn: jS(BiSbTe)/ jS(Pt) = 61

- Gain from W (θSHE = 0.33, lsf = 1.4nm) to α-Sn: jS(BiSbTe)/ jS(Pt) = 4.2

or with θSHE = 0.19, lsf = 1.4nm: jS(BiSbTe)/ jS(Pt) = 7.4

Compared charge to spin conversion yields

between

1) TI (Bi1-xSbx)Te3

with conversion factor jS/JC ≡ qICS ≃ 1nm-1

(Kondou et al, ArXiv:1510.03572) and

2) SHE-Pt or - W layers with jS/JC= ѲSHE /lsf in the optimal conditions t = lsf

1) Gain in ejected 3D spin current density JS

for the same 2D charge current density jC in metal layer or 2D topological states

between SHE with Pt or W (for t ≃ lsf ) and (Bi1-xSbx)Te3 (qICS ≃ 1nm-1 )

- Gain from Pt (θSHE = 0.056, lsf = 3.4nm) to α-Sn: jS(BiSbTe)/ jS(Pt) = 61

- Gain from W (θSHE = 0.33, lsf = 1.4nm) to α-Sn: jS(BiSbTe)/ jS(Pt) = 4.2

or with θSHE = 0.19, lsf = 1.4nm: jS(BiSbTe)/ jS(Pt) = 7.4

Remark: simple calculations lead to qICS = 1/vFτ and λIEE = 1/vFτ = vFτbut τ has not exactly the same meaning in qICS and λIEE

Summary

Spin-charge conversion in spintronics

-Spin-Orbit in 2D system (Rashba, TI, LAO/STO)

more efficient than in 3D (SHE)

for spin-charge conversion

- TI can work at RT (as well as Rashba interfaces)

- TI more efficient if topological 2DEG protected

by interface with insulator (ex: LAO/STO)

- Other TI-based devices: spin-filtering p-n

junctions, high-speed opto-spintronics, thermo-

electric applications ….

Thanks to all my coworkers

K. Garcia , J-M. George, H.Jaffres, N. Reyren, J-C Rojas-Sánchez,

CNRS/Thales


Oyarzun,. L. Vila, CEA Grenoble

J.M. De Teresa, Un. Zaragoza, Y. Ohtsubo, A. Taleb, SOLEIL Synchrotron

C.Rinaldi, M.Cantoni, R.Bertacco, Milano, R.Wang, R.Calarco, Berlin (Drude)

SPINHALL + SOSPIN

Tserkovnyak et al. PRL 88, 117601 (2002)

Spin pumping : generation of out of equilibrium spin distribution in FM and spin current injection in adjacent layer

22 2 2

2 2

int

20

4 4 4

8 4 4

rf s seff

s

sJg h M M

M

-200 -100 0 100 200

dX

''/d

H (

a.

u.)

H -Hres

(mT)

/4FM

BFM N eff

s FM

gg

M t

1) Increase of effective damping and FMR linewidth

K. Ando, E. Saitoh et al. JAP 108 , 113925 (2010)

etc

//Bi/Ag/NiFe

//NiFe

(1)

(2)

Y. Tserkovnyak et al. RMP 77, 1375 (2005)

Spin pumping from FMR

2) Injected spin current from g derived from

FMR

DFT-LDA for 44 ML

of 0.23% biaxially

strained α-Sn(001)

Helical spin polarization

DFT-LDA for 44 ML

of 0.23% biaxially

strained α-Sn(001)

They are localized near the

slab surfaces. Apart from

atomic oscillations in Fig.

2(c) the envelope shows a

localization near

the surface and an

exponential decay into the

bulk region of the slab with

a decay constant of about

10.1 A° . As consequence

the overlap of envelope

functions belonging to

opposite surfaces of the

slab with 40 ML is

negligibly small.

Helical spin polarization

EF – EDP with Ag

EF – EDP without Ag

Documents

Conversion between spin and charge currents by Rashba or ...people.ece.umn.edu/groups/cspin/events/tsd2016/... · Conversion between spin and charge currents by Rashba or Topological