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Inelastic X-Ray Scattering as a Probe of the Dynamics in Complex and Hybrid Materials
Alessandro Cunsolo (NSLS II-Brookhaven National Laboratory)
11th Conference on Inelastic X-Ray Scattering-IXS2019June, 23-28 2019
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Summary
• A brief introduction to phononics• The case of diluted NP suspensions• “Guiding” sound waves in water upon
confinement in carbon nanotubes• Perspectives
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What is phononics?
Phononic crystal have a structural arrangement deeplyinterfering with acoustic waves (phonons) of certainfrequencies which cause the latter to be reflected,trapped, slowed down or even stopped (phononic gaps)
J. Martinez-Sala et al. Nature 378, 241, (1995).
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From sonic to hypersonic frequencies
Liu, Z. et alk. Science, 289(5485), 1734 (2000).
The manipulation of ultrasonic waves requires assemblies structured at cm scales
D. Schneider et al. Nano Lett. 12, 3101 (2012)
Hypersonic waves can be “stopped” propagation gaps using materials structured in the µm-range
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Maldovan, Nature (2013)
Energy harvesting!!
Phononic crystals, metamaterials: artificial periodic structures made of two different elastic materials
cONTROL OF PHONON PROPAGATION IN COMPOSITE MATERIALS
Hangyuan Lv et al. Appl. Phys. Lett. 102, 034103 (2013);
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The phononic spectrum
MANIPULATION OF SOUND AND HEAT IN A LARGE FREQUENCY
SPECTRUM
MAINLY ORDERED, NANOSTRUCTUREDPHONON PROPAGATION INSIDE A HYBRID SYSTEM WITH INELASTIC X RAY SCATTERING
IXS
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Au nano-rods in water φ=10 nm, l=40 nm
0.05% (volume) concentration
0 200.0
0.1
0.2
0.3
0.00
0.05
0.10
0.15
0.0
0.1
0.2
0.3
I(Q,ω
)/I(Q
,0)
ω (meV)
Q = 3.57 nm-1
Q = 8.39 nm-1
Q = 6.81 nm-1
De Francesco et al. submitted to ACS Nano
-10 -5 0 5 100.0
0.3
0.00
0.05
0.10
0.150.0
0.1
0.2
Q = 7 nm-1
Q = 4 nm-1
Pure glycerol
NP suspension
in glycerol
ω (meV)
Q = 2 nm-1
I(Q
,ω
)/I(Q
,0)
4 6 8 10 12 14 16 18 20 22 24 26 28 300
1000
2000
3000
4000
5000
6000
First S(Q) peak of liquid glycerol
Inte
nsity
(cou
nts)
Q (nm-1)
Bragg peak from Au-NPs
Damping off collective modes of the hosting liquid in very diluted colloidal suspensions
Au nano-spheres in glycerol φ=10 nm 0.05% volume concentration
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-5 0 5 10 150.0
3.0x103
Q = 5.5 nm-1
-5 0 5 10 150.0
6.0x103
Q = 3.5 nm-1I(Q,ω
) (ar
bit.u
nits)
ω (meV)
Liquid water
Resolution ~1.5 meV
Suspension of Au nano-spheres crystal (φ=50 nm) in liquid water at room T volume concentration = 0.5 %
No apparent sign of the liquid collective dynamics
Small peaks emerge
Bayesian inference based hypothesis test on the number of modes k
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0 3 6 9 12 15 180
5
10
15
20
4 2 0
ω1,
2 (meV
)
Q (nm-1) Density of States
Au DoS, Lynn et al. (1973)
DISPERSION CURVES
The experiment can only probe the ongitudinal and transverse collective dynamics from Au NPsWater dynamics damped by NP-induced scattering of phonons with Au NP ?
-5 0 5 10 150.0
3.0x103
Q = 5.5 nm-1
-5 0 5 10 150.0
6.0x103
Q = 3.5 nm-1I(Q,ω
) (ar
bit.u
nits)
ω (meV)
LA (this work)TA (this work)LA liquid gold (Guarini et al, 2015)ω=cs Q (cs : sound velocity in liquid
Au)
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Water confined in nanotubes: few hints from existing literature
Two main evidences emerging fromthe large body of literature results:
• The confinement in CNTs induces alayered structure on water whichfavours diffusive flow in the axialdirection.
• Although this unidimensionalconfinement reduces the numberof hydrogen bonds it makes themmore directional and preferentiallydirected along the CNTs axis.
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The two scattering geometries considered
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A scheme of the a priori expected outcome
QQ in the radial
plane
Q
Q in the axial direction
Only transverse modes of watercanpropagate in the basal plane (⊥ Q)
Only longitudinal modes of water can propagate along the CNT axis ( Q )
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IXS spectra from the hydrated sample, the dry sample and the resolution
0.05
0.10
-15 -10 -5 0 5 10 15
0.01
Q = 11.95 nm-1
I(Q
,ω) /
I(Q
,0)
ω (meV)
Hydrated sample Dry sample
Resolution function
Possible "hints" of weak inelastic contribution
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0.001
0.01
0.1
1
0.001
0.01
0.1
1
-15 -10 -5 0 5 10 151E-4
0.001
0.01
0.1
1
Q (nm-1)
Q = 2 nm-1
Q = 3 nm-1
Hydrated aCNT Bulk water Resolution profile
I(Q
,ω)/I
(Q,0
)
Q = 5 nm-1
0 5 10 15 20 25 300
50
100
150
200
250
300
350
400 Hydrated sample Dry "
I(Q
) (ar
bit.
units
)
Q(nm-1)
The IXS and GISAXS measurements at NSLS II
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Multiple DHOs+δ(ω) modelling of the lineshape
100101102103104
103
104
105
Q= 6.94 nm-1
101
102
103
Inten
sity
(cou
nts)
102
103
104
105
Q=10.27 nm-1
-30 -20 -10 0 10 20 30101
102
103
104
E (meV)
-30 -20 -10 0 10 20 30103
104
105Q=13.55 nm-1
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The sound dispersion curves
0 5 10 150
2
4
6
8
10
12
14
16
18Ω
j (meV
)
Q(nm-1)
mode (hydrated sample) " " (dry sample) mode (hydrated sample) additional high-energy mode Transverse mode of bulk water , graphite
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Conclusion (I)
• The immersion of limited amount of nanoparticles appears a remarkably efficient method to damp off collective excitations in
liquids !
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Conclusion (II)
1) Axial (Out of plane) orientation of Q ⇒The hydrated array behaves as a nearly perfect acoustic damper for confined water, the only inelastic features surviving in the spectrum from hydrated aCNTs are phonons of the carbon matrix.
2) Radial (In-plane) orientation of Q ⇒ only the transverse mode is allowed to propagate through the CNTs. The hydrated array behaves as a polarization filter for acoustic excitations in water.
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nS
nHSpacer
Hybridization
Au particle10 nm
50 DNAs per particle
III: Development of new, programmable super-lattice assemblies of nanoparticles functioning as phononic
crystals: Using the most advanced nanotechnology we aiming at searching new hybrid metamaterials to
implement acoustic manipulation based upon structural engineering
Extension of phononics to the unexplored THz realm → implementation of heat flow management based uponthe design of nanostructure
II: Phonons propagation when the floating assembly is ordered: INS/IXS measurements on superlattice of NP suspended in water.Tunable structural parameters (bond strengths, distance), shape and size.
Simple method to manipulate heat transport through a slight perturbation of the liquid structure: new avenues in the emerging field of phononics ?
I: ice, other liquids, different NP and sizes, T, ……
Looking ahead
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