eric beaurepaire within organic spintronics: from simple ... · rise of organic spintronics weak...

Eric Beaurepaire within organic spintronics: from simple to functional molecules, from interfaces to devices

1959-2018

Institut de Physique et Chimie des

Matériaux de Strasbourg (IPCMS)

France

European Environmental Agency 2014

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Eric Beaurepaire within organic spintronics: from simple to functional molecules, from interfaces to devices

Institut de Physique et Chimie des

Matériaux de Strasbourg (IPCMS)

France

1959-2018

~1100 citations

100 -

1997 2017

Spintronics?

Use the electron spin in addition to its charge in electronics

• S. Bader, S.S.P. Parkin, Annu. Rev. Condens. Matter

Phys. 1, 71 (2010)

• Bader and Hoffmann, Phys. Rev. Appl. 4 047001 (2015)

Reviews / Outlooks

bowen

@unistra.fr

Rise of Organic Spintronics

Weak spin-orbit coupling

Long spin relaxation times

Why use Organic Semiconductors for

Spintronics?

bowen

@unistra.fr

Challenges

Demonstrate spin transport

across the organic layerAnd understand it!

Utilize molecular propertiesDevelop multifunctional devices

Ferroelectricity

Spin crossover…

Sanvito, Chem. Soc.

Rev. 6 3336 (2011)

First Results

Weak spin-orbit coupling

Long spin relaxation times

Why use Organic Semiconductors for

Spintronics?

bowen

@unistra.fr

2002: magnetoresistance (MR) (Dediu)

Dediu et al., Solid State Commun. 122, 181 (2002)

H=0

H=3kOeMR

T6 sexithiophene EF EFV0

P

AP

PAP RR

First Results bowen

@unistra.fr

2004: large MR across 100nm (Vardeny)Xiong et al, Nature 427, 821 (2004)

H=0

H=3kOeMR

T6 sexithiophene

Very thick layers

Diffusive Transport

Alq3

2002: magnetoresistance (MR) (Dediu)

Dediu et al., Solid State Commun. 122, 181 (2002)

Eric’s approach bowen

@unistra.fr

OMBE Metal MBE

Sputtering

Heterostructure growth

Structural/Electronic properties at ferromagnet/molecule interfaces

Synchrotron-based studies

+ Device-based studies

Single MoleculeSolid-state devices

Starting in 2003:

Integrate Functional Molecules

FerroelectricSpin Crossover

What is the spinterface?

Spinterface-based devices

Deploying molecular functionalities

AdsorptionMagnetismDOSSpin DOS

Spinterface: Adsorption

Atomic displacements

+ van der Waals interactions

Grimme et al., J. Comput. Chem. 27, 1787 (2006)

Barone et al., J. Comput. Chem. 30, 934 (2009)

Brede et al., Phys. Rev. Lett. 105 047204 (2010)

bowen

@unistra.fr

Adsorption distance matters!

Spinterface: Adsorption

Parameter-free theory to predict interface properties for

any metal/molecule pair (think systematics…)

Cu

Cu

Cu

MnPc

N

C2

C1

Mn

2.0 2.5 3.0 3.5 4.0

vdW

Adsorption Distance (Å)

GGAGGA-D2

DFT+vdW DFT

x-ray standing wave

technique (XSW)vdW-augmented

DFT

XSW

ID32

ESRF

MnPc

• flat molecule

• several atomic species

• several chemical sites

• no corrugation

Rare experiment

Difficult access

bowen

@unistra.fr

Measure & Predict Adsorption Distance ?

Ir/Gr: Busse, C. et al. PRL. 107, 036101 (2011).

Cu/MnPc: Javaid, … EB, PRB 87, 155418 (2013)

Spinterface: Magnetism bowen

@unistra.fr

• Magnetized molecule: 1st reportsScheybal et al., Chem. Phys. Lett. 411 214 (2005) Wende et al, Nat. Mater. 7 516 (2007)Javaid … EB PRL 105, 077201 (2010)

Spinterface: Magnetism bowen

@unistra.fr

• Magnetized molecule: C / N sitesNi/Gr: Appl. Phys. Lett. 96 012504 (2010) F. Djeghloul, … EB et al., Sci. Rep. 3 1272 (2013)

• Magnetized molecule: 1st reportsScheybal et al., Chem. Phys. Lett. 411 214 (2005)

Magnetism on N p bonds

Wende et al, Nat. Mater. 7 516 (2007)Javaid … EB PRL 105, 077201 (2010)

Co

Co

Co

MnN1CC CCN1

[001

]

[110]

3.6 Å

Spinterface: DOS

X-ray Absorption Spectroscopy

Takacs, EB et al, PRB 78, 233404 (2008)

Javaid … EB PRL 105, 077201 (2010)

Ab-initio Theory

Metallic Pc on Co

Tunneling begins from the

molecule

Cu(111)//CoPcCo(111)//CoPc

210-1-2Energy (eV)

LDO

S

Scanning Tunneling Spectroscopy

Met

allic

STS: Wulfhekel Group, KIT

XAS: SLS Synchrotron

bowen

@unistra.fr

Spinterface: spin-pol DOS bowen

@unistra.fr

Larger DOS in FM -> Larger energy broadening of Molecular level

Barraud et al, Nat. Phys. 6 615 (2010)Schmaus … EB et al, Nat. Nanotech. 6 185 (2011)Sanvito, Chem. Soc. Rev. 6 3336 (2011)Delprat et al, JPD:AP 51 473001 (2018)

Spin-polarized charge transfer

Spinterface: spin-pol DOS

-40

-20

0

20

40

-3.5 -3.0 -2.5 -2.0 -1.5

-5

0

5

10

EF

DO

S (

Arb

. U

nits)

MnPc Molecule

E (eV)

DO

S (

Arb

. U

nits)

EF

a

Dz=6.6Ǻ

z-D

OS

pl-DOS

Artificial

separation

bowen

@unistra.fr

Phthalocyanine

(Pc)

Dz=2.1Ǻ

• High spin polarization at room temperatureF. Djeghloul, … EB et al, Sci. Rep. 3 1272 (2013)

Spinterface: spin-pol DOS

-40

-20

0

20

40

-3.5 -3.0 -2.5 -2.0 -1.5

-5

0

5

10

EF

DO

S (

Arb

. U

nits)

MnPc Molecule

E (eV)

DO

S (

Arb

. U

nits)

EF

a

Dz=6.6Ǻ

z-D

OS

pl-DOS

Artificial

separation

bowen

@unistra.fr

Phthalocyanine

(Pc)

Dz=2.1Ǻ

• High spin polarization at room temperature

0

200

400

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

0

200

400

T = 300K

Spin

Spin

InverseDirect

Co(0

01)/

MnP

c(~

2M

L):

PE

at/

above

the s

pin

terf

ace (

Arb

. U

nits)

E-EF (eV)

• Metallic interface• High spin polarization at 300K

F. Djeghloul, … EB et al, Sci. Rep. 3 1272 (2013)

FM/molecule spinterfaces bowen

@unistra.fr

Sci. Rep. 3, 1272 (2013)

Carbon 87 269 (2015)

J. Phys. Chem. Lett.7, 2310 (2016)

F. Djeghloul, … E.B. et al,

A generic property

Spinterface Property testedRT

High P at EF?

Opposite FM surface &

spinterface P?fcc Co(001)/MnPc Initial report Yes Yesfcc Co(001)/H2Pc Initial report Yes Yesbcc Fe(001)/MnPc Fe vs Co Yes Yesfcc Co(001)/phen Other conjugated

moleculeYes Yes

fcc Co(001)/penta Non-conjugated molecule Yes Yesbcc Fe(001)/C60 Non-planar molecule Yes Yesfcc Co(001)/C60 Hybridization strength No Nofcc Co(001)/a-C Simplest spinterface Yes Yes

Spinterface

AdsorptionMagnetismDOSSpin DOS

Organic Spintronic Devices

Pc : Molecular Junctions

Cu(111)//Co/H2Pc

GMR ~ 60%Low resistance (metallic)Small area

Schmaus, EB et al, Nature Nanotech. 6, 185 (2011)

Kawahara … Repain/Barreteau, Nano Lett. 12 4558 (2012)

bowen@unistra.fr

H2Pc

Pc : Molecular Junctions

Cu(111)//Co/H2Pc

GMR ~ 60%Low resistance (metallic)Small area

bowen@unistra.fr

H2Pc

EF

EF

Co

Spin Selective Broadening of LUMO level

Schmaus, EB et al, Nature Nanotech. 6, 185 (2011)

Kawahara … Repain/Barreteau, Nano Lett. 12 4558 (2012)

Tunnel Junctions bowen@unistra.fr

Santos… Moodera, Phys. Rev. Lett. 98, 016601 (2007)Barraud et al., Nature Phys. 6, 615 (2010)

Xiong et al, Nature 427, 821 (2004)

LSMO / Alq3 / Co

~100nm~3nm

10-3mm2 10+6mm2

Device quality matters!

TMR > 0 TMR < 0

Tunnelling Diffusive

Maturing the spinterface bowen@unistra.fr

2010-2013

2013 -

Molecule alters Metal bowen@unistra.fr

Raman… Moodera, Nature 493 7433 (2013)

• Molecule-induced modification of surface magnetic anisotropy

• Interface MR

Magnetic Hardening@Spinterface

Molecule alters Metal bowen@unistra.fr

Magnetizing Cu using C60

Al Ma’Mari… Cespedes, Nature 524 69 (2015)

• Magnetometry• Muon spin rotation spectroscopy

Magnetic Hardening@Spinterface

Raman… Moodera, Nature 493 7433 (2013)

• Molecule-induced modification of surface magnetic anisotropy

• Interface MR

Maturing the spinterface bowen@unistra.fr

2010-2013

2013 -

2015 -

Molecular Spin Chains bowen@unistra.fr

Crystals / Thin Films Serri et al, Nature Comm. 4 3079 (2014)

Can reach high magnetic exchange energies!

Molecular Spin Chains bowen@unistra.fr

M. Gruber, … EB …, Nature Materials 14, 981 (2015)

@ Spinterface

Co

MnPc

‘Exchange Bias’ bowen@unistra.fr

S. Boukari, … EB, Nano Lett. 18 4659 (2018)

M. Gruber, … EB …, Nature Materials 14, 981 (2015)Co(20ML)/MnPc(25ML)/Au(20ML)

J/kB~100 K

Bairagi et al. PRL 114, 247203 (2105)Bairagi … Repain, PRB 98 085432 (2018)

In-s

itu

Spintronic Impact bowen

@unistra.fr

• Co/CoPc/Co: Combined TMR/TAMR + high coercive fieldsC. Barraud, … EB et al., PRL 114 206603 (2015)

• TAMR is both unidirectional + uniaxial

• Signature of spinterface/spin chains

T = 2K

Spintronic Impact bowen

@unistra.fr

Co/H2Pc/MnPc/Co

• High TMR (LT)C. Barraud, … EB et al., Dalton Trans. (2016)

Inelastic tunnelling

T = 2K

+ hints of AF spin chain excitations

Chain length?

MR

(%

)

Spin-flip Spectroscopy

Chen et al, PRL 101 197208 (2008)

Toward Active molecular spinterfaces

Cinchetti, Hueso, Dediu, Nat. Mater. 16 507 (2017)

Molecular hybridization• 3d Metals• Topological Insulators• Rashba Systems

• Skyrmion Lattices• 2D Materials

What is the spinterface?

Spinterface-based devices

Deploying molecular functionalities

Conclusions

Modulate SpinterfaceModulate (spin) transport

FerroelectricitySpin Crossover

Artificial Magnetoelectric bowen@unistra.fr

Electrical insert, DEIMOS @ Synchrotron SOLEIL

L. Joly… M. Bowen, P. Ohresser, J. Synchrotron Rad., (2016)

• Industrial-grade microelectronic devices

Two Classes of operando studies

Materials ScienceExcitation = X-ray photons

Probe(e.g. total electron yield)

Device is off

standard

Craft Device State

Theory: R. ArrasCEMES Toulouse

Artificial magnetoelectric

Organic spinterface

PZT/Co

Co/FePc

F. Djeghloul … EB …, J. Phys. Chem. Lett. (2016)

Vlasin… S. Cherifi,ACS Appl. Mat. & Int. (2016)

M. Studniarek… EB …,Adv. Func. Mater. 1700259 (2017)

Artificial Magnetoelectric bowen@unistra.fr

Electrical insert, DEIMOS @ Synchrotron SOLEIL

L. Joly… M. Bowen, P. Ohresser, J. Synchrotron Rad., (2016)

• Industrial-grade microelectronic devices

Two Classes of operando studies

Materials ScienceExcitation = X-ray photons

Probe(e.g. total electron yield)

M. Studniarek… EB …,Adv. Func. Mater. 1700259 (2017)

Device is off

standard

Craft Device State

Theory: R. ArrasCEMES Toulouse

Molecule

Reproducible changes to molecular magnetism at spinterface due to ferroelectric cycling

Active molecular spinterfaces

Cinchetti, Hueso, Dediu, Nat. Mater. 16 507 (2017)

Ferroelectric Spinterfaces bowen

@unistra.fr

Liang et al. Adv. Mater. 28 10204 (2016)EB and team, on-going research

Spin Crossover Molecules

280nm film

Shi… EB, APL 95, 043303 (2009)

NCS groups

Phen groups

CNRS-EWHA2014

38

bowen

@unistra.fr

FePhen

Thin film!

Single SCO molecule transport

280nm film

CNRS-EWHA2014

38

bowen

@unistra.fr

Requires CuN surface

Reduced Hybridization

Miyamachi … EB …, Nature Comm. 3, 938 (2012)

Tailor chemical environment

Zhang … Letard, Dowben et al, Adv. Mater. 1702257 (2017)

Preserving SCO on Metals

Custom SCO molecule w. central site protection(Mallah group)

bowen

@unistra.fr

[FeII((3, 5-(CH3)2Pz)3BH)2](1)(Pz ¼ pyrazolyl)

Au(111)//SCO(~1ML)

SCO preserved!

T = 5K

Bairagi … Repain, Nat. Comm. 7 12212 (2016)

Bairagi … Repain, J. Phys. Chem C 122 727 (2018)

LIESST

Toward SCO spinterfaces bowen

@unistra.fr

M. Gruber,… EB …, Nano Lett. 15 7921 (2015)

Also works for Co/Au/MnPc

In preparation.

Magnetism Spin-pol DOS

E. Urbain,… EB …, Adv. Func. Mater. 28 1707123 (2018)

T = 300K

T = 300KH = 0.1T

SCO Devices bowen

@unistra.fr

Molnar et al, Adv. Mater. 17003862 (2017)

Devid… Dowben, Doudin, ACS Nano 9 4496 (2015)

Challenging device physics!

Infer SCO property from phenomenology of T Dep.

SCO Devices bowen

@unistra.fr

Lefter … Bousseksou, Adv. Mater. 28 7508 (2016)

Separate photocurrent & LIESST contributions

SCO Devices bowen

@unistra.fr

Poggini et al, Adv. Elec. Mater. 1800204 (2018)Vertical device7nm thick SCO film

100x change in device current within 1K around SCO transition!

SCO Devices bowen

@unistra.fr

Schleicher … EB …, ACS Appl. Mater. & Interfaces 10 31580 (2018)

SCO transition using XAS

R(T)

Electrical readout of Fe site involvement in transport!

Eric & Organic Spintronics bowen

@unistra.fr

Last 15 years of his life

• Experimental

• Expertise Infrastructure

Spinterfaces

Functional Molecules

• Structure

• Magnetism

• DOS

• Spin DOS

• Spintronics

Functionalize the

spinterface

Multifunctional Electronics

(including spintronic)

Quantum Physics