Perspectivesexciting.wdfiles.com/local--files/cecam-talks-2012/Rubio.pdf · 2012-09-17 ·...

PerspectivesHoW exciting! Hands-on Workshop on Excitations 2012. HU Berlin, August 2-8, 2012

Workshop “Non adiabati

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”, Schloss Reisens

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2007

12th Density Functional Theory Conference, Amsterdam, August 2007

NanoBio Spectroscopy Group and ETSF Scientific Development CentreDpto. Física de Materiales, Universidad del País Vasco,

Centro Física de Materiales CSIC-UPV/EHU San Sebastián, Spainand

FHI Max-Planck-Gesellschaft, Berlin, Germany

http://nano-bio.ehu.es E-mail: [email protected]

Angel Rubio

Perspectives

“How Exciting Hands-on workshop on Excitations 2012”



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Towards atomic scale technologies: bottom-up approach

● Molecular electronics; Moore's law—---beyond Moore

● quantum information; communication

● photonic materials (holes) (“metamaterials”)

● Composite materials

● Alternative energies (photovoltaic, fuel cells, etc...)

self-assembly supramolecular chemistry



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Small is different: atoms and molecules as our building blocks

nano, bio and material science

More is different: emergent properties of matter

Computational Science: insight into the fields of Physics, Chemistry, Materials Science, Medicine, Biology, Astrophysics, Earth science, Energy, transportation, Domotics, ........

NEW CONCEPTS

Nanoelectronics + Nanoptics + Nanophononics



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NEW CONCEPTS


Economist, May2003



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Nanotubos de carbono: transporte de masa

B.C. Regan et al, Nature 428, 924 (2004)



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Why Theoretical Spectroscopy?

“Excitations”



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More is different: emergent properties of matter

*** time resolved spectroscopy (new basic and technological concepts): eg. attosecond dynamics (Free-electron lasers) (quantum control)

NEW CONCEPTS


Interrogating Molecules? (Nature)

Science, Nov. 2008 …........... and get an answer !!!



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Dark Structures in Molecular Radiationless Transitions Determined by Ultrafast Diffraction, Science, Vol 307, 558-563 (2005)



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Qbit-control

Leds and laser diodsefficiency

***Seeing is believing*****



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***Seeing is believing*****

if you understand what you see!!!

� � � � �m



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Back to the ground

“How Exciting! Hands-on Workshop on excitations”



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Science 321, 800 -803 (2008)

Methods for various materials properties



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Time and size scales



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DFT Success “~chemical accuracy”

Structural properties, stability, phononsPhase transitions Surface catalysis and chemical reactivityBiomodeling .................

Allows large scale simulations BUT.....



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........present XC-functionals usually fail in describing:

LEVEL ALIGNMENT (KS): DFT-Gap

Long-range potential (atom/molecule)

Dispersion forces VdW, Solvation

Charge-transfer, multiple excitations

Memory effects; Dissipation; lifetime; de-coherence

Open shell systems and Open quantum systems

Correlated Materials ...............



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LEVEL ALIGNMENT, Dispersion forces VdW

Aromatic molecules on

Cu(110)

N. Atodiresei, S.Blugel et al, PRL 102, 136809 (2009)

See the talk of P. Rinke for CO on surfaces

Supramolecular chemistry

Biophysics ..........

Molecular Transport



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LEVEL ALIGNMENT, Dispersion forces VdWCharge Transfer excitationsPhotovoltaic Hybrids: Grätzell

cells

Road to Improving Efficiency: Controlling position of the frontier orbitals



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4

5

6

7

8

9

10

11

Vac

uum

NaC

l(001

)

MgO

(001

)

CaO

(001

)

BaO

(001

)

TiO

2(00

1)

Gra

phite

Al(1

11)

Pt(

111)

Rh(

111)

Ti(0

01)

Li(0

01)

BaO

(11

1)

HO

MO

-LU

MO

Ga

p (

eV

)

GW

LDA

4

5

6

7

8

9

10

11

Vac

uum

NaC

l(001

)

MgO

(001

)

CaO

(001

)

BaO

(001

)

TiO

2(00

1)

Gra

phite

Al(1

11)

Pt(

111)

Rh(

111)

Ti(0

01)

Li(0

01)

BaO

(11

1)

HO

MO

-LU

MO

Ga

p (

eV

)

PBE0

LDA

LDA gaps are independent of substrate and distance

Same result with other functionals (GGA, hybrid or exact exchange)

GW gaps show large variation across different surfaces

GW gap sensitive to atomistic details screening is very important

The CT process at interfaces is a dynamical one

Illustrative Example: physisorbed benzene

4

5

6

7

8

9

10

11

Vac

uum

NaC

l(001

)

MgO

(001

)

CaO

(001

)

BaO

(001

)

TiO

2(00

1)

Gra

phite

Al(1

11)

Pt(

111)

Rh(

111)

Ti(0

01)

Li(0

01)

BaO

(11

1)

HO

MO

-LU

MO

Ga

p (

eV

)

GW

LDA



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Correlated materials

Sensitivity

Emergence

Phase transitions with pressure doping or temperature

Interface between correlated oxide insulators? It is metallic!



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What is correlations and when a system is to be considered correlated? ...beyond LDA ? … beyond HF?

How much of the “model hamiltonian” studies can be captured by present “advanced” functionals



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Correlation

SIMPLE MODEL SYSTEMS

How to understand H2

and H-chain

(Mott insulator in DFT)



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The step in KS potential

Early work of Perdew, Almbladh& von Barth, Gritsenko & Baerends Recent work of Tempel, Martinez, Maitra, JCTC (2009) and N. Helbig, I. Tokatly, A. Rubio, JCP (2009)

●Step aligns the atomic HOMOs ●Kohn-Sham system builds a ”wall“ to mimick the repulsion due to interaction and prevent tunneling

Prevents dissociation to unphysical fractional charges●Step-height = difference between highest eigenvalues of the two wells



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VK

S- V

ion

icH-chain Mott insulator: in DFT !!!

Clearly all local functionals and most orbital dependent functionals do not capture the step in the potential

The KS systems is metallic : fxc responsible for the gap



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Open question

How to incorporate/model this efect into static and time-dependent DFT ?



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(Some) Open questions

* Tunneling and/or CT processes at interfaces ??? Open questions

* Related concepts: * Molecular dissociation: bumps in Vxc * Electron tunneling * Rabi Oscillations

* Dissipation; lifetimes; de-coherence, Non adiabatic couplings

* Quantum control and open quantum systems

Work to be done: “new spatial and frequency-dependent functionals”

.



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Some active ? Fields for first principles modeling ??



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The Problem with Determining Atomic Structure at the Nanoscale

Science 27 April 2007 316: 561-565

Examples of nanostructured materials. (A) Nanostructured bulk materials. (B) Intercalated mesoporous materials. (C) Discrete nanoparticles. In each case, ball-and-stick renditions of possible

structures are shown on the top, and TEM images of examples are shown on the bottom.



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J.Phys.Chem.B 108, 9646, (2004)

Electron transfer processes in molecular devices



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Excited-state properties of confined water as it permeates through nanochannels: Nanosolvation



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Azobenzene: spectroscopy along femtosecond laser induced photoisomerization

S. Spörlein et al, Proc. Natl. Acad. Sci., 99, 7998 (2002)

HOMO

LUMO

T. Hugel et al, Science, 296, 1103 (2002) Y. Yu et al, Nature 425, 145 82003)

Azobenzene dyes are known to isomerize at the central N-N bond within fractions of picoseconds at high quantum yield [T. Nägele et al, Chem. Phys. Lett. 272, 489 (1997)].

Single-Molecule Optomechanical Cycle



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Fuel cellsGrätzel cellsphotovoltaics

ENERGY APPLICATIONS



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Towards the color of plants: e.g. Spinach

Fleming et al Nature (2005),.... (Berkeley)



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Excitations in bio-systems: encouraging results!!Green fluorescent protein and their mutants (2008, Nobel prize in Chemistry)

(Aequorea victoria: jellyfi sh)

M.A.L Marques, X. Lopez, D. Varsano, A. Castro, and A. R. Phys. Rev. Lett. 90, 158101 (2003)

Some biophysical processes



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Quantum control

R. J. Levis et al, Science 292, 709 (2001)

Time resolved pump-probe techniques



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Optimal control theory

Key question: What is the laser pulse that drives the system intoa predefi ned goal?

Procedure: Defi ne a target operator Ô and at the end of thelaser interaction (t = T) maximize the functional

W. Zhu, J. Botina, H. Rabitz, JCP 108, 1953 (1998)

Ô = |Φ > <Φ |F F target state

Example: High harmonic generation and selective bond-breaking



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Tailoring HHGHHG consists of the emission of integer multiples of the carrier frequency of a driving laser, due to its highly non-linear interaction with matter. It can be explained with the so-called 3-steps model:

Typically, the HH spectrum (emission intensity vs. photon frequency) consists of a rapid intensity decrease, a plateau, and a cut-off.



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Tailoring HHG

Tailoring femtosecond light pulses in the IR-UV regime permits to access molecular vibrations, and therefore control chemical reactions.

The natural time scale of the electrons is, however, in the attosecond regime. In order to control electrons, we need sources with XUV energies and attosecond pulse durations.

HHG is viewed as a possible source of coherent radiation in the XUV and soft X-ray regime.

HHG permits to produce trains of attosecond-length pulses.



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Tailoring HHG

7th 13th



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The combination of MBPT and (TD)DFT is a powerful tool to “predictive” describe the combined

dynamics of electron/ion in response to external electromagnetic fields of large scale nanostructures, biological molecules and extended systems spanning

very different time scales

ETSF



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It is one of the frst duties of a professor, for example, in any

subject, to exaggerate a little both the importance of his subject and

his own importance in it

G. H. Hardy (1940). A Mathematician's Apology.

http://www.cambridge.org/catalogue/catalogue.asp?isbn=9780521427067



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Nanotechnology: a higher form of evolution? (Humility is perhaps appropriate…)



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Than

k yo

u!!!!

For more details see:http://nano-bio.ehu.eshttp://etsf.eu

http://etsf.eu/



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Acknowledgements

N. Helbig, J. Fuks, A. Crawford, J.Walkenhorst, L. Stella, I. Tokatly, S. Kurth

ETSF , Dpto Material Physics, Centro Mixto CSIC-UPV, Donostia, Spain

E. K. U. Gross MPI-Halle

N. Maitra Hunter College NY C.A. Rozzi

A. Castro BIFI, Zaragoza H. Appel FHI-Berlin



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K. Kriger, A. Castro, E.K.U. Gross, (unpublished)



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Perspectivesexciting.wdfiles.com/local--files/cecam-talks-2012/Rubio.pdf · 2012-09-17 ·...

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