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Serguei Brazovskii and Natasha Kirova Natal 2012 Physics of synthetic conductors as low dimensional correlated electronic systems. Lecture 1 : Overview and History. The course purposes: Acquaintance with wonders of synthetic materials at levels of materials, experiments, theory.

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SergueiBrazovskii and Natasha Kirova

Natal 2012

Physics of synthetic conductors as low dimensional correlated electronic systems.

Lecture 1 : Overview and History

The course purposes:

Acquaintance with wonders of synthetic materialsat levels of materials, experiments, theory.

Using them for tutorial purposes of the condensed matter physics.

Learning general concepts of cooperative electronic states.

Introduction to peculiarities and richness of low-dimensional many-body systems.

The planning: flexibility governed by our mutual interactions.

synthetic conductors”, “synthetic metals” –

a narrow traditional name certified by titles of the major journal and the major chain of international conferences.

Actually they are versatile materials designed for purposes of :

Bringing material with necessary electronic, optical, properties for applications;

challenging big goals like all-organic superconductors, ferroelectrics, ferromagnets;

amusing us with interplay of cooperative correlated states;

playgrounds for theories of low-dimensional interacting systems;

accessing very general issues of cooperative and dynamic phase transitions, nonlinear, nonstationary behavior of many-body systems, concentrated in physics of solitons

Brazil connections: polymers for electronic and optical applications, from Rectify to San Paolo. Theory of solitons from Natal to Rio de Janeiro and MatoGrosso.

« In the beginning was the Word, …

and without him was not anything made that was made »

Physical Review 1964 & Scientific American 1965

W.A. Little , Stanford University

Possibility of a synthesizing an organic superconductor.

Superconductivity at room temperature.

It has not yet been achieved, but … it is possible to synthesize organic materials that … conduct electricity without resistance.

Little drawing: conjugated polymer -

the polyene backbone with ligands R

Superconductivity: Tc ~ ħωphexp(-1/λ)

λ–coupling of electrons to vibrationswith a frequencyω~1/ M1/2

Ready or waiting for applications:

Polymers for Light Emitting or Harvesting

& Organic Ferroelectrics





What shall we learn in terms of materials and their physics?

Classes of synthetic metals:

inorganic chain compounds,

  • conducting polymers,organic crystals,


Inorganic world of d-electrons:

K2Pt(CN)4Br0.3H2O , NbSe3 , andsuperconducting ! polymer (SN)x



The ever richest phase diagram of electronic phases.

CO – Charge Ordering

AFM – Anti-FerroMagnetism

SDW – Spin Density Wave

SP – Spin-Peierls

SC – Superconductivity

H axes – field-induced density waves, quantum Hall, oscillating cascades


Phtalocyanine – a borderline of worlds of p and d electrons.

Its stacks can be both conducting because of p-electrons of the ring,

and magnetically active because of the transition metal core.

These crystals show a metal – insulator transition due to formationof an electronic crystal – a CDW. Its breakdown due to the spin polarization in a high magnetic fieldgives rise to periodic lattices of solitons.

Diverse and advanced experimental techniques:

Angle Resolved Photoemission - ARPES

It sees the dispersion, delocalization, and the band structure of conducting organic stacks

Here, for the double-stackedorganic crystal TTF-TCNQ

creation of soliton at Es=2D/p

The STM sees the Charge Density Wave –

a crystal of electronic pairs with one embedded soliton

The nano-scale tunneling device fabricated by focused ion beamsallows to see the same solitonin dynamics

The same setup gives an access to reconstruction of the nano-junction of the CDW by propagation and final installationof topological defects – the dislocations of the electronic crystale.i. the vortices of the CDW complex order parameter.

Amplitude of the CDW

Results of computer simulations.

From experiments to the nature and to fancy theories

Theoretical modeling of the soliton and its mathematical relation to irregularities of ocean waves at beaches of Natal.

Modeling for the same amplitude soliton = SPINON

- the gap node carrying

Spin=½ but Charge=0

The Tsunami soliton appears as

a particle for 1D fermions with

spontaneous mass generation:

Gross-Neveu model in Field

Theory, Charge Density Waves.

All that is associated to the KdV

nonlinear equation.

Fundamental physical properties and calls to theories
Fundamentalphysicalpropertiesand calls to theories:

Solitons in quasi one dimensionalsystems.

  • Multi-electronictheory of solitons and their superstructures: exact solutions of variousmodels.

  • Mutualeffects of electronic and structure properties.

  • Cooperativeeffect of solitons’ ensemble: phase transitions, aggregation, hydrodynamics.

  • Optical and charge transferproperties of conductingpolymers.

Recent events in physics of quasi one-dimensional conductors

related to physics of solitons.

Routes to a role of microscopic defects in

general strongly correlated electronic systems.

Solitons/instantons in electronic properties:Born in theories of late 70’s, Found in experiments of early 80’s.

Why in 2000’s ? New conducting polymers,New events in organic conductors, New accesses to Charge Density Waves,New inhomogeneous-nonstationarystrongly correlated systems

Can the solitons cross the boarder to the higher D world ?Are they allowed to bring their anomalies like spin-charge separation or mid-gap states?Password : confinement – recall Quarks in QCD.

spin flipping

spin rotations

by hole motion

Various scenarios :

  • Compensation by the gapless mode

  • Aggregation into domain walls versus their melting by thermal deconfinement or long rage Coulomb forces

  • Coupling to structural defects in polymers.

  • Binding to kink-antikink pairs.

  • Topological binding to gapless degrees of freedom

Collective motion and plasticity of electroniccrystals.

  • Frohlich conduction – by the collective sliding of charge and spin densitywaves.

  • Topologicaldefectsrelated to the charge densitywaves: solitons, dislocations.

  • Problems of the current conversion.

  • Phase slips as instanons.

Contact properties of non traditionalsemiconductors.

  • Electric field and charge penetrationinside the polymer via solitons and solitonlattices.

  • Possibility of superconductivity on the metal-polymer interface.

  • Charge densitywaves and solitonsuperlatticesnear the contacts.

  • Generation of dislocations on the contact. Field effect for the charge densitywaves.

2000’s accelerating mainstream in the condensed matter physics:

IMPACT transformations of electronic states/phases under strong external influences. The confluence of two streams:

A. Electrostatic doping = Field-Effect transistor

with extremely high electric fields to reach

a critical surface concentration of carriers.

Main target: switching on or off the superconductivity or the Mott state.

Successes: Geneva U., Brookhaven NL, Tokyo U, Cambridge.

B. Persistent or short-lived transformations

induced by a high power laser pumping.

Ingredients: femto-second resolution pump and probe optics,

pico-second evolution of the transformed states.

Latest versions: Optical pulses followed by the new

time-resolved ARPES or X-ray diffraction.

Successes: Tokyo U., Sendai U., Ljubljana-Slovenia, Oxford, Hamburg, Konstanz, Orsay, … more.

Next coming jump – atto-seconds.

Real-time physicsfemto-second probe of evolving ground state with a spontaneous symmetry breaking – the Charge Density Wave


A- waves

Observation of thedynamical phase transition and of the domain walls annihilation