eric beaurepaire within organic spintronics: from simple ... · rise of organic spintronics weak...
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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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Of Science & Society
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)
H2Pc
Pc : Molecular Junctions
Cu(111)//Co/H2Pc
GMR ~ 60%Low resistance (metallic)Small area
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 [email protected]
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
Molecule alters Metal [email protected]
Raman… Moodera, Nature 493 7433 (2013)
• Molecule-induced modification of surface magnetic anisotropy
• Interface MR
Magnetic Hardening@Spinterface
Molecule alters Metal [email protected]
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
Molecular Spin Chains [email protected]
Crystals / Thin Films Serri et al, Nature Comm. 4 3079 (2014)
Can reach high magnetic exchange energies!
Molecular Spin Chains [email protected]
M. Gruber, … EB …, Nature Materials 14, 981 (2015)
@ Spinterface
Co
MnPc
‘Exchange Bias’ [email protected]
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 [email protected]
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 [email protected]
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