SPECTROSCOPY OF 1D MATERIALS IN SINGLE ...maruyama/visitors/Kuzmany...Filling from Process...
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SPECTROSCOPY OF 1D MATERIALS IN SINGLE-WALLED CARBON NANOTUBES H. Kuzmany Fakultät für Physik der Universität Wien, Wien, A Content THE SQUEEZED SPACE INSIDE Filling the tubes MAGNETIC PEAPODS ESR, rotor state, tuning the pea distance DOUBLE-WALLED CNTs: Pair spectra, catalytic growth 13 C SWCNT: NMR, spin gap, Tomonaga-Luttinger behavior Co-operations U Wien TU Budapest Oxford U IFW Dresden AIST Tsukuba U Erlangen U Paris Sud MPI Dresden U Sofia U Bologna FeCp 2 @(10,10)
Transcript of SPECTROSCOPY OF 1D MATERIALS IN SINGLE ...maruyama/visitors/Kuzmany...Filling from Process...
SPECTROSCOPY OF 1D MATERIALS IN SINGLE-WALLED CARBON NANOTUBES
H. KuzmanyFakultät für Physik der Universität Wien, Wien, A
Content
THE SQUEEZED SPACE INSIDEFilling the tubes
MAGNETIC PEAPODSESR, rotor state, tuning the pea distance
DOUBLE-WALLED CNTs:Pair spectra, catalytic growth
13C SWCNT: NMR, spin gap,Tomonaga-Luttinger behavior
Co-operationsU WienTU BudapestOxford UIFW DresdenAIST Tsukuba U ErlangenU Paris Sud MPI DresdenU SofiaU Bologna
FeCp2@(10,10)
0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.00.00.51.01.52.02.53.03.54.04.55.0
Es33
Em11
Es22
Inverse Diameter (nm-1)
Tran
sitio
n En
ergy
(eV)
Es11
0.7 0.50.60.81.01.21.6Diameter (nm-1)
2.0
KATAURA PLOT
Hans Kuzmany: PHYSICS OF CARBON NANOPHASES
Fig. 6.12
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Fig. 6.12 H. Kataura et al., Synth. Met.103 (1999) 2555-2558 (modified) Due to the proportionality of the transition energies to 1/dt the energies can be plotted in a linear Diagram versus the inverse tube diameter (Kataura plot). Small deviations from linearity appear for small tube diameters and for high transition energies. They originate from deviation of the band structure of graphene from an ideal cone (trigonal warping). The blue board marks the visible spectral range. The dashed red line connects transitions for one tube.
The squeezed space inside
150 200 250 300 350 4001,5
1,6
1,7
1,8
1,9
2,0
2,1
2,2
2,3
2,4
2,5
2,6
Eii (e
V)
RBM Frequency (cm-1)
FAMILY BEHAVIOR FOR RBM RAMAN RESONANCES
Popov-Kataura plot
Open symbols: Symmetry adapted non orthogonal TBv. Popov 2003 +corrections
Filled symbols:experiment, HiPco(averaged from Fantini et al., Telg et al., 2004)
(6,4)
(7,2)
(8,0)
DWCNT
22
16
17
19
2024
27Families: (2n+m) mod 3 = 0, 1, 2
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In the diameter range of the inner shell tubes the family behavior of the tubes is very well expressed. 2m+n (3) = 0 (metallic), 2m+n (3) = 1 (sc I), 2m+n (3) = 2 (sc II) Fam 16: (6,4), (7,2), (8,0); Fam 17: (6,5), 7,2), (8,0) Fam 19: (7,5), (8,3), (9,1); Fam 27: (9,9), (10,7), (11,5), (12,3), 13,1)
500 1000 1500 2700Nor
mal
ized
Inte
nsiti
es (a
rb. u
.)
Raman shift (cm-1)
vRBM = C/d(n,m)
RAMAN SCATTERING FROM SWCNTs
RBMD
G
G‘
647
488
14 Raman active modes (8 for zig-zag, armchair)
All Raman lines disperse!
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From the four Raman lines three are highly dispersive. Whereas the D-line and the G‘-line exhibit a continuous up shift with increasing laser energy the RBM-line shows characteristic line pattern for each laser.
DOUBLE RESONANCE SCATTERING FOR D-LINE AND G‘-LINE
Double resonance for graphite
Triple resonance for nanotubes
G‘
Disp
DISPERSION OF G-LINESVienna Ab initio Simulation Package, VASP
selected modes
O. Dubay et al., PRL 2002
(T)
O. Dubai et al., PRL2002
DWCNT
Filling SWCNTs
FILLING SINGLE_WALLED CARBON NANOTUBES
B The filling processes Filling from Process characterization Examples Vapour phase
Clean but thermal stability of filler is required
C60, C70, metallofullerenes
Liquid phase (melt)
Simple if melt exists Medium filling temperature
Alkali halides, ferrocene
(Solution) Low temperature but solvent may also enter
Fullerenes, N@C60, C59N
Supercritical CO2
Clean, low filling temperature but needs special equipment to handle sc CO2 , long filling times
Functionalized fullerenes
A Opening the tubesexposure to air at 450-650 0C, 2 h re-closing is possible by heating in vacuum at 800 0C, 6 h
S. Iijima (2004)
K. Suenaga IWEP2006
K. SuenagaWONTON 2005
Fig.6.32
J. Sloan (2002)
Hybride filling: C60-FeI2
Doped PeapodMetallofullerenes
T. Okazaki (2005)
1D MATERIALS @ SWCNTs
Classical peapod
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Fig. 6.32 TEM images, various authors, 2005/2006 Top left: alternating filling of tubes with C60 and FeCl2 Top right: peapods, after doping with potassium. The potassium atoms are inside the tubes. Bottom left: functional fullerenes make chemical bonds to the tube from the inside Bottom right: reactions of the C60 molecules with each other (fusion process)
EXPERIMENTAL OBSERVATION OF PEAPODS
Fig. 6.31
150 300 450 600 750 1350 1500 1650
Inte
nsity
(arb
. u.)
x10
RBM Hg(4
)H
g(3)
A g(1)
x50
Raman shift (cm-1)
488.0 nm, 90 K
Hg(2
)
D-m
ode
A g(2)
Hg(7
)
x10
G-m
ode
x1
Raman scattering
R. Pfeiffer, 2003
Filling with magnetic peapods (N@C60, C59N)
Transformation to DWCNT
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Fig. 6.31 R. Pfeiffer, J. Bernardi (2003) Left: TEM picture of peapods, as recorded by J. Bernardi at the TU Wien Right: Raman spectrum of peapods; the red circled lines come from the tubes, the other sharp lines from the C60 molecules
Magnetic peapods
S i k
LINEAR SPIN CHAINS WITH C59N@SWCNTs
for C59N:S=1/2I = 1
Dimer
C59N-XM2
Spin Engineering
322 324 326
C59N:C60@SWCNT
600 oC vac.ES
R si
gnal
(arb
.u.)
C59N-XM2:C60@SWCNTBefore heat treatment
N@C60:C60
Magnetic Field (mT)
F. Simon et al., PRL 2006
Spinconcentration is only about 10% of C59N-XM2concentration!
Spinconcentration is only about 10-6
Spinconcentration zero
C
Heterodimer
Heterodimer
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Linear spinchains with C59N@SWCNTs
250 300 350 400 4500.0
0.2
0.4
0.6
0.8
I hete
rodi
mer/I to
tal
T (K)
F=E-TSIhetero/Itotal=1/(1+expΔF/kBT
)Ebinding=2800 K, S2-S1=9kB
DYNAMICS OF THE SPIN CARRYING STATE
Heterodimer/monomer
Ground state: spins at C60-> siglet state
Excited state: spins at C59N -> hyperfine triplet
0,09
0,10
0,11
0,12
0 50 100 150 200 250 3000,00
0,02
0,04
0,06
0,08
860660460
260
60
a)
hombroadening T1fit
b)ΔH
(mT)
ΔHH
om (T
)
Temperature (K)
T1 (nsec)
T (K)
C59N:C60@SWCNT
Monomer:motional narrowing!
Heterodimer:Korringa behavior
F. Simon, PRL 2006
ON TRANSFORMATION TO DWCNT: IS N INSERTED INTO THE INNER-SHELL TUBE?
expected: 0.14% line shift
RBM: 0.5 cm-1
2D: 3.5 cm-1
observed: 2D: 3 cm-1
2430 2520 2610
Red: DWNT transformed from (C59
N)2@SWNT
Blue: DWNT transformed from (C60)n@SWNTBlack: SWNT
Raman shift (cm-1)
Ram
an In
tens
ity (a
rb. u
nits
)
1064 nm, 80 K
15481545
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Oberton der D Linie gemessen mit 1064 nm Laser
Double-walled carbon nanotubes, pair spectra
Linewidths down to 0.4 cm-1
10x more narrow than for standard tubes
The interior is a Nano-cleanroom
100 200 300 400 500 600 700 800 1300 1400 1500 1600
Nor
mal
ized
Inte
nsity
(arb
. u.)
x20 90 Kx50 x20 x1
Raman shift (cm-1)
SWCNTs
C60 peapods
DWCNTs
inner RBMsx5 x5
Pfeiffer et al., PRL2003
RAMAN
GROWING DWCNTs FROM PEAPODS
There are too many lines!!
RAMAN MAP
RBM RAMANLINESDWCNT vs CoMoCat
The two cluster of lines originate from the same inner tube((6,5), (6,4))
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Tube-Tube interaction is responsible for the splitting. More than one type of tube can grow in a particular outer tube and vice versa.
Color code: Raman Intensity
RESONANCE PROFILE OF CLUSTER COMPONENTES
All lines in the in the cluster come from the same inner but different outer tubes.
Lase
r Ene
rgie
Phononen Frequenz
-2 mV/cm-1
R. Pfeiffer et alPRB 2005
330 335 340 345 350 355 360 365
Exp.
Inte
nsity
(arb
. u.)
RBM frequency (cm-1)
Exp: intensity normalized by cross section
COMPARISON OF CLUSTERED LINES WITH CALCULATION
Exp: intensity normalized by cross section
(6,4)
(6,4)
V. Popov, 2005Continuum model
(6,4)
(6,4)
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Experiment: normale Auflösung
COMPARISON OF CLUSTERED LINES WITH CALCULATION
Calculatd with Gaussian profilPair spectra
V. Popov, 2005Continuum model
Exp: intensity normalized by cross section
(6,4)
(6,4)
R. Pfeifferet al. 2005
FERROCENE IN SWCMTs
No Raman spectrum could be observed after filling at 100 0C for several daysFeCp2
H. Shiozawa et al., 2007
2 h, 600 0C
1 h, 1150 0C
Photoemission spectroscopy
150 200 250 300 350 400
(FeCp2)n@SWCNTs, 1150°C, 1h (FeCp2)n@SWCNTs, 600°C, 8h (C60)n@SWCNTs, 1150°C, 24h
676 nm (1.83 eV), 80 K, NR
Sca
led
Inte
nsoi
ty (a
rb. u
.)
Raman shift (cm-1)
RAMAN SCATTERING FOM FeCp2 AND C60 GROWN DWCNTs
290 300 310 320 330 340 350 360 370
(6,4)
(17,
3),(1
5.6)
(16,
2), (
14,5
)
(14,
7),(1
8,1)
(13,
8),(1
6,4)
(12,
9),(1
1,10
)(1
7,2)
,(15,
5),(1
8,0)
(14,
6),(1
6,3)
,(13,
7)(1
7,1)
,(12,
8)
(14,
6) (11,
9),(1
5,4)
,(10,
10)
Nor
mal
ized
inte
nsity
Raman shift (cm-1)
(13,
6)
S
(17,
0)
(16,
3)
A
B
C
(6,5)a
600 0C
C601150 0C
1150 0C
a) As filled
b) After heat treatment at 1150 oC
c) after heat treatment at 600 oC
d) Fe3C particle with simulation
a b c
d
HR-TEM FOR FERROCENE FILLED SWCNTs
K. Suenaga, 2007
Fe3C+C
FeCp2
Growth from catalytic reaction
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D: schwrze Punkte sind Fe, färbige Punkte (lila) Fe3C Simulation (Pbmn, a=0.4523 , b=0.5089 , c=0.6743 nm Bei längerer Auslagerung bei 600 oC wandelt sich das Fe-Karbid in Fe-Oxid um. Fe-Ox ist außerhalb der Röhrchen
13C precursor grown DWCNT
150 200 250 300 350
676 nm
12C60-DWCNT
12-13C60-DWCNT
Ram
an si
gnal
(a.u
.)
Raman shift (cm-1)
RBM line
1260 1280 1300 1320 1340 1360 1380 1400
29%13C60 DWCNTs
12C60 DWCNTs
568 nm
Inte
nsity
(arb
. u.)
Raman shift (cm-1)
19 cm-1
D line
SPECTROSCOPY FOR 13C-SWCNT
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Fig. 8.17 F. Simon et al. 2005, unpublished P.M. Singer et al., NMR Evidence for Gapped Spin Excitations in Metallic Carbon Nanotubes, Phys. Rev. Lett. 95, (2005) 236403 NMR: T1 aus free induction decay nach /2 Impuls(3usec), M(t) gestreckte Exponentialverteilung. Feldabhängigkeit : 1/T1T = A+B/H wie für 1D Leiter, 1/T1T wird aus n() berechnet nach: 1/T1T = α()n()n(+)(-f(T, )/), α() wird aus A+B‘/ berechnet. Der Überschuss im Maximum von 1/T1T könnte LL Verhalten sein. Okazaki beobachtet quenching der Lumineszenz!!!
CHECKING THE ROLE OF TOLUENE
2500 2600 2700 2800 2900
1.1 %
515 nm, RT
26.5 %
54 %
74 %
Ram
an si
gnal
(arb
.u.)
Raman shift (cm-1)
13C enriched toluene+C60
0 10 20 30 40 50 60 70 800
2
4
6
8
10
12
x=1
x=74
x=54
x=26.5
1.1+0.130(6)*x
13C
enr
ichm
ent o
f inn
er tu
bes (
%)
13C content of toluene (%)
As evaluated from the RBM first spectral moment
Singer et al., PRL 2005
From spin-echo sequence
13C-SWCNT@12C-SWCNTsRELAXATION OF MAGNETIC MOMENTS
stretched exponential [ ]β)/(exp)0()( 1
eTtMtM −=
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2 Orders of magnitude enhancement of sensitivity, 89% 13C enhancement Signal recovery after saturation magnetization yields M(t), t/Te1 is a scaled relaxation time. Not equal 1 means a distribution of T1. Te1 prop to mean relaxation time <T> (T1e=<T>/Γ(1/), Γ is gamma function)
LONGITUDINAL NUCLEAR SPIN RELAXATION T1
prop H1/2
Singer et al., PRL 2005
Description by a gaped DOS
DYNAMICS OF NUCLEAR SPINS
1D spin diffusion Korringa relaxation
1/TT1exp= 940 (μsK)-1
1/TT1 = A + B/√H
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Field dependence of 1/TT1 = A+B/√H. B-term is typical for 1D spin diffusion (electron spin diffuse, cut off for small fields is not yet reached. A is the nondiffusive part to the relaxation Korringa: The correct slope is obtained for the dipole-dipol interaction (r=aCC) and the correct n(F) which depends on tube diameter (n(F = (2√3/π2Vpp)(a/d)
i) High T: 1/TT1 constant, independent from Tfor all tubes, Korringa behavior
ii) T<150K: 1/TT1 increases dramatically
iii) Below 20 K a spin gap appears
Description with a gaped DOS, Δ = 20 K,
-0,1 0,0 0,1
DO
S (a
rb.u
.)
E(eV)
2Δ
RESULTS FROM NMR RELAXATION
Origin of gap:Not field-induced (independent of field
Not curvature-induced (100 meV expected)
Not longitudinal quantization (distribution expected)
Possible: Peierls or spin-Peierls gap
Origin of metallization:Intertube interaction
Charge tansfer
W. Song et al. 2005
METALLIZATION FROM TUBE-TUBE INTERACTION
From first principle calculations
(V. Zolyomi et al. 2007)
General: gap closes or at least gets reduced
TOMONAGA-LUTTINGER DESCRIPTION FOR T1
For 1D electronic system a correlated ground state is expected ->
TL-liquid instead of Fermi liquid
H. Ishii et al., 2003from PES: α =0.46 (g=0.18)
TLL is described by bosonization of the fermions
The FL description above uses a gap already at room temperature wich violates 2Δ/KBTc > 3.52 rule(mean field not applicable)
Here: TLL (ungaped) and Luther- Emery (gaped) description were combined
B. Dora et al., PRL 2007
At low T:a spin gaped LEL
Above 30K: normal TLL
Summ
SUMMARY
The inside of SWCNTs: a narrow space for preparation of new structures.
1D materials from magnetic molecules can be prepared inside.
Nanotubes growth inside: clean room conditions
Raman line pattern of the RBM modes for DWCNTs: pair spectra
Catalytic reactions inside: tube growth at 600 0C
13C DWCNTs: with inner tubes almost exclusively 13C. Raman: G’-anomalyNMR: inner tubes: metallic, with a spin gap of 3.5 meV appearing at 20 K,Best described by TLL and LE liquids
ACKNOWLEDGEMENT
Co-worker, in Wien international Projects R. Pfeiffer A. Janossy (TU Budapest) FWF, Projekt 14893 F. Simon V. Popov (U Sofia, Namur) Projekt 17345 M. Milnera H. Alloul (U Paris Sud) Projekt 14386 T. Pichler (+IFW Dresden) F. Singer (U Paris Sud) M. Hulman K Suenaga (AIST, Tsukuba) W. Plank H. Kataura (AIST, Tsukuba) EU, FUNCARS H. Peterlik A. Hirsch (U Erlangen) PATONN H. Shiozawa (IFW Dresden) NANOTEMP IMPRESS
