Frontiers of SPM, 5 Oct. 2006 The nanomechanics of

Presentación de PowerPointInstituto de Microelectrónica de Madrid
Ricardo García
Outline
ii). The physics of phase Imaging: elastic vs. Inelastic processes
iii). Identification of energy dissipation Quantitative information
iv). Enhancing Force Sensitivity: Beyond 1st mode Imaging
v). Summary
Instituto de Microelectrónica de Madrid
10 nm
a
GroEL in liquid, T. Ando et al. PNAS 98, 12468 (2001)
PM in liquid, D.J. Muller et al. Biophys. J. 77, 1150 (1999)
50 nm
8 nm
verified values
Resolution*
Liquid 1 PM crystal
DNA entropic elasticity
0.01-10 0.8 L
DNA intrinsic elasticity
10-70 0.8-1 L
Forces and Resolution in AM-AFM (biomolecules)
Laboratorio de Fuerzas y TLaboratorio de Fuerzas y Túúnelnel
tip’s oscillation
Free amplitude
Amplitude modulation AFM (AM-AFM)
ω/ω0
SIMULATION
R= 10 nm, A0=10 nm, zc=8 nm, E=1 GPa, k=40 N/m, f0=325 kHz
Free oscillating tip (10 nm ) Interacting tip (10 nm size )
Mechanics of vibrating nanosystems:
AS Paulo, R García, PRB 66, 041406(R) (2002)
Resonance Curves
0.5
1.0
(a)
A m
pl itu
de (n
Tip-surface separation (nm)
Simulation data: R=20 nm f0=350 kHz, Q=400, H=6.4x10-20, E*=1.52 GPa
0
45
90
135
180
6
9
12
15
18
H
L
Garcia, San Paulo, PRB 61, R13381 (2000); Garcia, Pérez, Surf. Sci. Rep. 47, 197 (2002)
simulations Exps.
φ
Driving signal:F(t) = F0cos(wt)
The dynamic response of the cantilever is modified by the tip-surface interactions
Phase Imaging
1 μm
10 nm
a
GroEL in liquid, T. Ando et al. PNAS 98, 12468 (2001)
Polymer morphology and structure as a function of temperature. Hydrogenated diblock copolymer (PEO-PB). Crystallisation of PEO blocks occurs individually for each sphere (light are crystalline, dark amorphous). Reiter et al., Phys. Rev. Lett. 87, 2261 (2001) Phase Image,
size 1μm2
PHASE CONTRAST
ELASTIC CONTRIBUTIONS
INELASTIC CONTRIBUTIONS
TOPOGRAPHIC EFFECTS
Sources of Phase Imaging Contrast

−+><−
>< =
ts
c
ω=ω0 and A>>z0The virial theorem applied to the tip allows to deduce
0
The phase shift depends on the sign of the interaction
0 45 90
Phase shift and tip-surface interactions
Phase shift and energy dissipation
ωπ=ω= ∫ sin)·(AkA)Q/1(dt dt dz)tcos(FE 00EXT
0
Tamayo, García APL73, 2926 (1998)
sp
dissp
Asp=cte.; phase shifts are linked to tip-surface inelastic interactions
)cos( φω −+= tAzz 0
Q πkA
A A)
A A(sinφE
2 0
00 dis −=
Asp=cte
0.2 0.4 0.6 0.8 1.0 0.0
0.2
0.4
0.6
0.8
1.0
Fixed by the observer A0,Q,k,ω0, ω
Q πkA
A A)
0
2
4
6
8
s pe
rc yc
le (e
10 15 20 25 30 35 40 45 0
20
40
60
80
100
120
140
160
180
Z piezo displacement (nm)
attractive regime (low amplitude)
repulsive regime (high ampl.)10 15 20 25 30 35 40 45
0
20
40
60
80
100
120
140
160
180
From Phase shifts to energy dissipation
The dissipated energy is higher on the repulsive regime Dissipation avoids artefacts due to regime changes of contrast
0.0 0.2 0.4 0.6 0.8 1.0
0
1
2
3
4
5
6
7
8
9
10
11
Attractive Repulsive
E d is p e r c y c le ( e V )
A/A 0
Applications of Phase Imaging
Identification of Nanoscale dissipation Processes
A0 = 40 nm, E=150GPa, Zc =20 nm; ΔH=1 Ei=33mJ/m2; Ev=66 mJ/m2; k=2N/m, Q=150
-0.05 0.00 0.05 0.10 -8
-6
-4
-2
0
2
N )
A0 = 6.6 nm, E=150GPa, Zc =3 nm. ΔH=2.5 Ei=20mJ/m2. Ev=40 mJ/m2
0 1
2 dd dz
-1 0 1 2 -6
-5
-4
-3
-2
-1
0
1
2
d (nm)
dissipa tion
A0 = 15 nm, η= 500 Pa.s; E=500MPa; Zc =6.5 nm
dt dRvF δδη=
Dissipation at the Nanoscale: viscoelasticity
0.0 0.2 0.4 0.6 0.8 1.0 0.0
0.2
0.4
0.6
0.8
Amplitude Ratio (A/A0) 0.0 0.2 0.4 0.6 0.8 1.0 -6
-4
-2
0
2
4
Analogy: Tersoff-Hamann theory of STM
)z,T(eV,)(EeV)(E dV dIG pFF φρρ ××+∝≡ TipSample
Red: viscosity
Blue: long range adhesion hysteresis
Black: short range ad. hystersis
The derivative of the dissipative energy singles out the dissipative process
Garcia, Gomez, Martinez, Patil, Dietz, Magerle, Phys. Rev. Lett. 97, 016103 (2006).
Long range dissipation adhesion hysteresis viscoelasticity
50n m 500 nm50n
-1
0
1
10
20
30
0.0
0.2
0.4
0.6
0.8
1.0
2
4
6
8
10
(f)
-0.5
0.0
0.5
1.0
5
10
15
tip-sample distance (nm)
)
The components of higher order modes and harmonics are several orders of magnitude smaller than the fundamental
50 μm
10-4
4x10 -4
8x10 -4
1x10 0
high amplitude
no rm
al iz
ed a
m pl
itu de
(b)
10-4
1 high amplitude
(b)
10-4
Process Force (pN) length scale
DNA entropic elasticity
0.01-10 0.8 L
DNA intrinsic elasticity
10-70 0.8-1 L
0 1
-8
-6
-4
-2
0
2
Improving force sensitivity
Forces t
txwbh t
txwatxw xL
CSIC, CNR (F. Biscarini) , Utwente (J. Vancso) , Ludwig-Maximilians- Universität (R. Stark), Chemnitz University of Technology (R. Magerle) , Universidad Autónoma de Madrid (R. Pérez), Nanoworld (C. Ritchter ) , Johannes-Kepler University (P. Hinterdorfer) , Electrónica y Diseño Aguado (I. Rodriguez)
Multipurpose Force Tool for Quantitative Nanoscale Analysis and Manipulation of Biomolecular, Polymeric and Heterogeneous Materials
ForceToolForceTool : NMP4: NMP4--CTCT--20042004--013684013684
Patents: PCT/ES 2006/070016; PCT/ES 2006/070096
ForceTool: Proposal submitted: 12 May 2004; final: 28 October 2004;
Project started: 1 February 2005
AFM controller
ForceTool AFM
0 2 0 0 4 0 0 6 0 0 8 0 0 1 0 0 0 1 2 0 0 1 4 0 0 -3
-2
-1
0
1
2
P h
a s
e S
h if
t (º
Δφ1
X (nm) 0 2 0 0 4 0 0 6 0 0 8 0 0 1 0 0 0 1 2 0 0 1 4 0 0
-3
-2
-1
0
1
2
P h
a s
e S
h if
t (º
Δφ1
0 2 0 0 4 0 0 6 0 0 8 0 0 1 0 0 0 1 2 0 0 1 4 0 0 -3
-2
-1
0
1
2
P h
a s
e S
h if
t (º
Δφ1Δφ1
Sexithiophene on Si(100)
-2
-1
0
1
2
X (nm) 0 200 400 600 800 1000 1200 1400
-3
-2
-1
0
1
2
-2
-1
0
1
2
ForceTool Phase shift
Tapping mode phase shift
Phase Imaging
Application 2: Measurement of material properties
The 3D character of the microcantilever allows to develop methods based on elastic processes. ForceTool Sensitivy is 100 times higher than in AM-AFM.
Two routes to compositional contrast: Conservative and non- conservative processes.
Agradecimientos
European Commission: ForceTool
Prof. Ricardo García
The nanomechanics ofCompositional Mapping byAmplitude Modulation AFM
Forces and Resolution in AM-AFM (biomolecules)
Amplitude modulation AFM (AM-AFM)
Phase Imaging
How to measure dissipation in amplitude modulation AFM
From Phase shifts to energy dissipation
The dissipated energy is higher on the repulsive regime Dissipation avoids artefacts due to regime changes of contrast
Identification of Nanoscale dissipation Processes
Dissipation at the Nanoscale:Surface Adhesion Hysteresis
Dissipation at the Nanoscale:viscoelasticity
The derivative of the dissipative energy singles out the dissipative process
Identification of dissipation mechanisms
Beyond 1st mode Imaging
Multipurpose Force Tool for Quantitative Nanoscale Analysis and Manipulation of Biomolecular, Polymeric and Heterogeneous Mate
ForceTool AFMNon-linear dynamics Nanomechanics, material design
ForceTool AFM
Tapping mode vs. ForceTool mode
Two routes to compositional contrast: Conservative and non-conservative processes.
Thank you for your attention!

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Frontiers of SPM, 5 Oct. 2006 The nanomechanics of