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
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
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,
Inorganic world of d-electrons:
K2Pt(CN)4Br0.3H2O , NbSe3 , andsuperconducting ! polymer (SN)x
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.
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
Solitons in quasi one dimensionalsystems.
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.
by hole motion
Various scenarios :
Collective motion and plasticity of electroniccrystals.
Contact properties of non traditionalsemiconductors.
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
Observation of thedynamical phase transition and of the domain walls annihilation