inelastic x-ray scattering as a probe of the dynamics in ... · crystals: using the most advanced...

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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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8

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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