B.I.Verkin Institute for Low Temperature Physics and Engineering, National

1. B.I.Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 61103 Kharkiv, (Ukraine) Centre of Low Temperature Physics Faculty of Science P.J. Šafárik University & Institute of Experimental Physics SAS, Park Angelinum 9, 041 54 Košice, Slovakia GRAPHENE AND GRAPHITE INTERCALATED BY METALS E.S.Syrkin 29.05.2009

2. QUASI-PARTICLE SPECTRA OF METALLIC STRUCTURES CONTAINING GRAPHITE À.Feher S.B.Feodosyev, I.A.Gospodarev, V.I.Grishaev, K.V.Kravchenko, E.V.Manzhelii, E.S.Syrkin ABSTRACT The construction of a graphite model and the calculation of the phononspectrum of such a model are presented. The quasi-Dirac peculiarities inspectra of phonon polarized perpendicularly to layers is found. The changesof phonon spectra due to intercalation and the inuence of defects on theelectron-phonon interaction in graphen and graphite are found and analyzed PACS: 63.20.-e

3. PART 1 Mikhail I. Katsnelson

4. Carbon is one of the most intriguing elements in the Periodic Table. It forms many allotropes, some known from ancient times (diamond and graphite) and some discovered 10-20 years ago (fullerenes and nanotubes). Interestingly, the two-dimensional form (graphene) was only obtained very recently, immediately attracting a great deal of attention. Electrons in graphene, obeying a linear dispersion relation, behave like massless relativistic particles. This results in the observation of a number of very peculiar electronic properties – from an anomalous quantum Hall effect to the absence of localization – in this, the first two-dimensional material. It also provides a bridge between condensed matter physics and quantum electrodynamics, and opens new perspectives for carbon-based electronics.

5. A two-dimensional form of carbon Fig. 1 Crystal structures of the different allotropes of carbon. Three-dimensional diamond and graphite (3D); two-dimensional graphene (2D); one-dimensional nanotubes (1D); zero-dimensional buckyballs (0D).

6. Discovery of graphene In 2004, a group of physicists from Manchester University, UK, led by Andre Geim and Kostya Novoselov, used a very different and, at first glance, even naive approach to obtain graphene and lead a revolution in the field. They started with three-dimensional graphite and extracted a single sheet (a monolayer of atoms) using a technique called micromechanical cleavage. Graphite is a layered material and can be viewed as a number of two-dimensional graphene crystals weakly coupled together – exactly the property used by the Manchester team.

7. Crystallographic structure ofgraphene Fig. Crystallographic structure of graphene. Atoms from different sublattices (A and B) are marked by different colors..

8. Electronic structure of graphene Fig. 7 Electron and hole cyclotron mass as a function of carrier concentration in graphene. The square-root dependence suggests a linear dispersion relation. Fig. 3 Band structure of graphene. The conductance band touches the valence band at the K and K’ points.

9. Electronic structure of graphene What makes graphene so attractive for research is that the spectrum closely resembles the Dirac spectrum for massless fermions. The Dirac equation describes relativistic quantum particles with spin ½, such as electrons. As a result, quasiparticles in graphene exhibit a linear dispersion relation

10. Electronic structure of bilayer graphene For two carbon layers, the nearest-neighbor tight-binding approximation predicts a gapless state with parabolic bands touching at the K and K’ points, instead of conical bands (massive fermions). At larger energies, bilayer graphene can be treated as a gapless semiconductor.

13. PART 2 Graphite Crystal Structure

14. Уравнения движения и силовые постоянные для разных типов связи

15. 11 силовых постоянных:

16. Изгибная жесткость слоев

17. Упругие модули:

18. Связь упругих модулей с силовыми постоянными и параметрами решетки Условие перехода уравнений динамики решетки в уравнения теории упругости

20. Нейтронографические данные…

21. Межслоевое взаимодействие • Потенциал Леннард-Джонса

23. Результаты:

25. PART 3 QUASI-PARTICLE SPECTRA OF METALLIC STRUCTURES CONTAINING GRAPHITE The construction of a graphite model and the calculation of the phononspectrum of such a model are presented. The quasi-Dirac peculiarities inspectra of phonon polarized perpendicularly to layers is found. The changesof phonon spectra due to intercalation and the inuence of defects on theelectron-phonon interaction in graphen and graphite are found and analyzed

29. Plans Алотропные формыуглерода.

30. Plans Structure of C2Li Structure of C6Yb Structure of the interlayer state. (a) An isosurface of the charge density associatedwith the lowest interlayer band in C2Li at the Г point. The colourmap on the left plane shows theprojection of the band density, with blue corresponding the low and red to high electron density. (b) The spatial structure of the interlayer band is essentially identical to that of its unoccupied analoguein pure graphite, which is shown in panel (c).

31. High-temperature superconductivity in layered iron compounds (FeAs system) M.V. Sadovskii, Yu.A. Izyumov, E.Z. Kurmaev, A.L. Ivanovskii (Kamihara Y et al J. Am.Chem.Phys.130 3296 (2008) Basic experimental data are presented for a new class of high-temperature superconductors, layered iron compounds of the typesREOFeAs (RE . La, Ce, Nd, Pr, Sm, ...), AFe2As2 (A . Ba, Sr, ...), AFeAs (A . Li, ...) and FeSe(Te). The electronic spectra of thesecompounds are discussed, including the effect of correlations and the spectrum and role of collective excitations (phonons and spin waves). Basic models for describing various types of magnetic ordering and Cooper pairing are reviewed. This is the first systematic review of a new class of high-Tc superconductors which includes iron-based layered compounds of the typesREOFeAs (RE: a rare earth element), AFe2As2 (A: Ba, Sr, Ca), LiFeAs, etc., all of which are antiferromagnetic metals whenstoichiometric and become superconducting (with a Tc maximum currently of 55 K) when doped with elements of different valence.The common structural element for all these compounds is layers of FeAs4 complexes. The electronic states near the Fermi level areformed by Fe 3d-states.

44. Thank You