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NSLS-II Workshop March 15, 2004 László Forró School of Basic Sciences Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials
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Page 1: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

NSLS-II Workshop

March 15, 2004

László Forró

School of Basic Sciences

Ecole Polytechnique Fédérale de Lausanne

Laboratory of Nanostructures and Novel Electronic Materials

Page 2: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Metals Semiconductors

Novelconductors,

bad metals

Our interest in solid state physics

Page 3: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

In Nanostructures

Page 4: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Protein

…and in Biomaterials

DNA

Keratocyte Neuron

Protein Protein polymer

Page 5: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Solid State Physics

Page 6: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

High Tc sample: Bi2Sr2CaCu2O8

Tc = 91 K

Studied at U4IR

Page 7: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

00 0.2

hole per CuO2

Tempe

ratu

re

anti

ferr

omag

neti

c

superconducting

T*

Non-Fermi liquid

Fermi liquid

Phase diagram

Pseudo-gap

Optimallydoped

underdoped overdoped

∆? Goal: to study the superconducting gap

Page 8: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

How can we study ∆ (at NSLS)?• Electron in - electron out

– EELS : SC → vacuum keV– Tunnelling : SC → metal meV

• Photon in - electron out– Photoemission eV

• Electron in - photon out– Inverse Photoemission

• Photon in - photon out– Optical reflectivity– Optical transmission meV– Raman scattering

• 300K = 25 meV = 200cm-1 = 6 THz• Low Tc : 3.5x3K = 100 GHz µwave• High Tc : 3.5x100K = 230cm-1 FIR

Our choice

Page 9: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Low Tc 1/τ ≈ 1013 Hz, 2∆ ≈1010 Hz

ω

σ1 σ21/ω

2∆ ω

2∆2∆ω ω

1.r

t

σdc

Total brightness

Total darkness

In transmission it is « easier » !!

refl

ecti

vity

tran

smis

sion

1

0

Page 10: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Reference paper!

Page 11: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

2212 100 nm thick single crystal, self-supported over 0.9 mm hole, platinum substrate

Our method:transparent single crystals of Bi2Sr2CaCu2O8

2212 150 nm thick single cystal, self-supported over 0.6 mm hole, contacted for resistivity, sapphire substrate

Page 12: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

The first « good » results (from U4IR)

No peak in transmission ratios -> gaplesssuperconductivity!

Forró et al., PRL, 65, 1941 (1990)

Page 13: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Counter-argument for the absence ofthe gap feature: Clean limit

2∆

T>Tc

1/τ

σ1

ω (cm-1)Very small oscillatory strength → Difficult to observe

Page 14: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 200 400 600 800

ρ ab (m

Ωcm

)

T (K)

Bi2Sr

2Ca

1-xY

xCu

2O

8

p=0.16

0.12

0.096

0.08

0.058

T*

0 100

1 102

2 102

3 102

4 102

5 102

6 102

0 50 100 150 200 250 300

R (Ω

)

T (K)

p = 1bar

0.1

0.01

0.001

Bi2Sr

2CaCu

2O

8+δ

Leaving the « clean limit » by introducingdefects: by electron irradiation, off-stoichiometry, substitution

e.g.: by Oxygen depletion

Page 15: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Infrared transmission of 2212 up to high temperatures (500 °C) (U4IR)

Thermocouple

Gold coated sapphire holder

heater

electrodes

Reference hole φ =0.6 mm2212 sample

Page 16: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Leaving « clean limit »:e-beam induced defects, heattreatment, substitution – still no gap feature!

Mandrus et ak, 70, 2629 (1993)

Cuprates are unconventional, d-wave superconductors!

Page 17: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

2zd

)( 2 gte

Recent work: BaVS3correlated d-electron system (on U10A)

Page 18: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Pressure dependence

L. Forró, R. Gaál, H. Berger, P. Fazekas, K. Penc, I. Kézsmárki and G. MihályPhys. Rev. Lett. 85, 1938 (2000).

Phase diagram

Page 19: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Optical conductivity in the infrared rangeambient pressure under pressure

C. Homes, et al. – NSLS U10A beamline (2001-2002)

∆ = 700 K

100 10000

100

200

300

400

500

600

700 p TMI ∆

18 kbar 17 K 260 K 16 kbar 26 K 320 K 15.7 kbar 27 K 390 K 14.6 kbar 31 K 410 K 1 bar 70 K 750 K

σ 1 (Ω

-1cm

-1)

ω (cm-1)

10 K

HP optical cell

Page 20: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Blue bronzePeierls transition at 180 K

Quasi-1D organic CDW conductors2H-NbSe2: a conventionallayered superconductor

Other correlated systems studied (U4IR)

Page 21: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Nanostructures – carbon nanotubes

Page 22: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Hernadi et al., Catalysis Lett. 59, 229 (1997)

Supporter (Alumina, Zeolite)

Catalyticparticles(Fe, Co, Ni…)

Single walled CNTs Multi walled CNTs

Page 23: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Structured Nanotube Filmsby Soft Lithography

1 mM 10 mM

40 mM 50 mM

Kind et al., Langmuir (2000)

Patterned CNT structures

Page 24: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Logic circuit – IBM (Derycke et al, Nanoletters, New York Times (2001)

Page 25: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Flat panel screen

ZnO phosphor(anode)

Mo gate (for pixel control)Nanotube emitters

Back contact

to emitters

(cathode)

Substarte

Glass

Samsung:

4.5" color screen

Choi et al., APL 75, 3129 (1999)

Page 26: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

IR microspectroscopy of nanotubes (on U10B)

– Gives local, chemically sensitive information

Page 27: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Example: optical conductivity of aligned ropes of carbon nanotubes

• Pure SWNTs Rope

Page 28: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

•Good metallic behavior for E||

Drude fit for E||:ε0 4.71

ωp 7300

γ 1200

•Large anisotropy

R. Gaál et al., in preparation

Parallel olarization

Perpendicular polarization

300 K

Experiment on SWNT ropes

Page 29: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Biomatter

Page 30: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

• Insulates like diamond (Broun et al., Nature’98)

• Semiconducts (Porath et al., Nature’2000); Tran et al., Phys.Rev.Lett.’2000).

• Conducts like a metal (Fink et al., Nature’99).

• Superconducts (proximity effect) (Kasumov et al. Science’2001).

Charge Transport in DNA

Page 31: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Aligned bundle of λ-DNA

Self-supportedoriented DNA bundle,

~10µm width

Light polarized ||and ⊥ to the bundle

Coppergrid

Page 32: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

0100 200 3000

Wavenumber (cm-1)

100

Tra

nsm

ittan

ce (%

)

400

A broad, localised

mode

No conduction in d.c. limit

the low energy part… (on U12IR)

L. Forró et al., in preparation

Page 33: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Results… (on U10B)

2000 4000 6000500Wavenumber (cm-1)

0

100

Tra

nsm

ittan

ce (%

)

Parallel polarization

Perpendicular polarization

Page 34: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Phonon structure of a protein: their variationcan be used for diagnostic purposes

0

0.2

0.4

Wavenumber (cm-1)4000 2000

Inte

nsit

y

N-H stretch in proteins C-H

stretch in lipids

C=O stretch

in α-helix

PO2stretch

Page 35: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Alzheimer’s plaques are misfol -ded β-amyloid protein.

Alzheimer’s tangles are hyper-phosphorylated tau protein the forms paired helical filaments.

Plaques and tangles are thought to damage surrounding neurons.

Plaques-like structures, by staining, have recently been identified in other organs: liver, pancreas, ovary, testis, thyroid.

Amyloid plaques

Neurofibrillary tangles

20 µm

20 µm

Normal Alzheimer’sAlzheimer’s disease

Page 36: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

1800 1500 1300

Wavenumber (cm-1)

Inte

nsit

y(u

.a.)

AD brain byopsis

α-helix

β-sheet Humain cortexhealthy

Alzheimer’s disease

Conformation change of a protein

Page 37: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Cortex AD plaques

140

120

100

80

60

40

20

0

y p

ositi

on [µ

m]

150100500 x position [µm]

0.80

0.75

0.70

0.65

intensity a.u.

Page 38: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Pancreas β-sheets plaques

Page 39: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

“You can observe a lot,

just by watching…”

Conclusion

Page 40: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Acknowledgments…G. Williams H. BergerLarry Carr R. Gaal

Lisa Miller A. Radenovic

Laszlo Mihaly A. Kis

C. Homes

D. Mandrus J. Miklossy

M. Martin S. Kasas

I. Kezsmarki

G. Mihaly

N. Barisic

Page 41: Ecole Polytechnique Fédérale de Lausanne · Ecole Polytechnique Fédérale de Lausanne Laboratory of Nanostructures and Novel Electronic Materials. Metals Semiconductors Novel conductors,

Thank you for your attention