ANNUAL REPORT - MTA SzFKI

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B.3. B.4. B.5. B.6. B.7. B.8. B.9. Kis-Szabó * K, Szépfalusy P, Szirmai * G; Phases of a polar spin-1 Bose gas in a magnetic field; Phys Lett A; 364, 362-367, 2007 Környei * L, Iglói F; Geometrical clusters in two-dimensional random-field Ising models; Phys Rev E; 75, 011131/1-6, 2007 Iglói F, Juhász R, Zimborás * Z; Entanglement entropy of aperiodic quantum spin chains; Europhys Lett; 79, 37001/1-6, 2007 Lin * YC, Iglói F, Rieger * H; Entanglement entropy at infinite randomness fixed points in higher dimensions; Phys Rev Lett; 99, 147202/1-4, 2007 Iglói F, Lin * YC, Rieger * H, Monthus * C; Finite-size scaling of pseudo-critical point distributions in the random transverse-field Ising chain; Phys Rev B; 76, 064421/1-5, 2007 Karsai * M, Anglès d'Auriac * JCh, Iglói F; Rounding of first-order phase transitions and optimal cooperation in scale-free networks; Phys Rev E; 76, 041107/1-7, 2007 Pleimling * M, Iglói F; Nonequilibrium critical relaxation at a first-order phase transition point; Europhys Lett; 79, 56002/1-6, 2007 B.10. Juhász R; Weakly coupled, antiparallel, totally asymmetric simple exclusion processes; Phys Rev E; 76, 021117/1-13, 2007 B.11. Juhász R, Zimborás * Z; Entanglement entropy in aperiodic singlet phases; J Stat Mech; P04004/1-18, 2007 B.12. Kunz * H, Livi * R, Sütő A; The structure factor and dynamics of the helix-coil transition; J Stat Mech; P06004/1-22, 2007 B.13. Menyhárd N, Ódor * G; One-dimensional spin-anisotropic kinetic Ising model subject to quenched disorder; PhysRev E; 76, 021103/1-9, 2007 B.14. Csordás * A, Almásy * O, Szépfalusy P; New universal quantities characterizing inhomogeneous Fermi gases at the Feshbach resonance; Europhys Lett; 80, 50002/1-6, 2007 B.15. Patkós * A, Szép Zs; Phase structure and phase transitions of the SU(2) × O(n) symmetric scalar field theory; Europhys Lett; 79, 51001/1-6, 2007 B.16. Kovács * P, Szép Zs; The critical surface of the SU(3) L × SU(3) R chiral quark mode at non-zero baryon density; Phys Rev D; 75, 025015/1-10, 2007 B.17. Herpay * T, Szép Zs; The boundary of the first order chiral phase transition in the m π - m K plane with a linear sigma model; Nucl Phys A; 785, 174-177, 2007 See also E.15. 12
C. ELECTRONIC STATES IN SOLIDS J. Kollár, P. Fazekas , K. Kádas, B. Lazarovits, I. Tüttő, B. Újfalussy, A. Virosztek + , L. Vitos, V. Zólyomi Traditionally, new materials have been developed by empirically correlating their chemical composition, and the manufacturing processes used to form them, with their properties. Until recently, metallurgists have not used quantum theory for practical purposes. However, the development of modern density functional methods means that today, computational quantum mechanics can help engineers to identify and develop novel materials. Besides, we demonstrate that computational modeling based on modern firstprinciples alloy theory can yield fundamental physical parameters with high accuracy. We illustrate this in a few examples. Using first-principles quantum-mechanical theory, we demonstrate that the surface chemistry of Fe-Cr alloys follows the peculiar threshold behavior characteristic to ferritic stainless steels. We find that in dilute alloys the surfaces are covered exclusively by Fe, whereas for bulk Cr concentration above ~10 % the Cr-containing surfaces become favorable. The two distinctly dissimilar surface regimes appear as a consequence of two competing magnetic effects: the magnetically induced immiscibility in bulk Fe-Cr alloys and the stability of magnetic surfaces. Using density-functional theory formulated within the framework of the exact muffin-tin orbitals method, we investigate the stability of the body-centered-cubic phase of Be (β- Be). The elastic constants and Debye temperature of β-Be are calculated over a wide volume range and compared to those obtained for the low temperature hexagonal phase (α-Be). A significant difference in the anisotropy of the bcc and hcp structures is found. In line with experiments, we predict that the hcp→bcc phase transition occurs at 240 GPa at 0 K and 239 GPa at ambient temperature. We find that the cubic shear constant C’=(C 11 −C 12 )/2 rapidly decreases for volumes above ~1.05V 0 , where V 0 is the zero temperature equilibrium volume for β-Be. At 1.17V 0 , the stability condition C’>0 is violated and the bcc phase becomes mechanically unstable. We demonstrate that at 0 K, the softening of β-Be near its experimental volume of 1.063V 0 is related to an electronic topological transition due to the increased number of occupied s states near the Fermi level compared to that at V 0 . This softening turns out to be important for the stability of the bcc phase before melting. The disclosed electronic topological transition is found to be present in other analogous hexagonal metals as well. First-principles calculations show that measured surface core-level shifts (SCLSs) of the GaAs(100)(2x4) surfaces can be described within the initial state effects. The calculated As 3d and Ga 3d SCLSs for the β2 and α2 reconstructions of the GaAs(100) (2x4) surfaces are in reasonable agreement with recent measurements. In particular, the results confirm that both the lower and the higher binding energy SCLSs, relative to the bulk emission in the As 3d photoelectron spectra, are intrinsic properties of the GaAs(100) (2x4) surfaces. The most positive and most negative As shifts are attributed to the third layer As atoms, which differs from the previous intuitive suggestions. In general, calculations show that significant SCLSs arise from deep layers, and that there are more than two SCLSs. Our previously measured As 3d spectra are fitted afresh using the calculated SCLSs. The intensity ratios of the SCLSs, obtained from the fits, show that as the heating temperature of the GaAs(100) (2x4) surface is increased gradually, the area of + Permanent position: Budapest University of Technology and Economics 13
Page 1 and 2: ANNUAL REPORT 2007 RESEARCH INSTITU
Page 3 and 4: Dear Reader, It is my pleasure to h
Page 5 and 6: Key figures Permanent staff of the
Page 8 and 9: A. STRONGLY CORRELATED SYSTEMS J. S
Page 10 and 11: presented detailed study should hel
Page 12 and 13: B. COMPLEX SYSTEMS F. Iglói, R. Ju
Page 16 and 17: the α2 reconstruction increases on
Page 18 and 19: C.2. C.3. Kádas K, Vitos L, Johans
Page 20 and 21: C.27. Ropo * M, Kokko * K, Punkkine
Page 22 and 23: I 25 4 3 Fig. 2. Average intensity
Page 24 and 25: See also H.6. and nanostructured Pd
Page 26 and 27: Ab initio structure solution. — I
Page 28 and 29: ESA PECS 98021 Phase field modeling
Page 30 and 31: Conference proceedings E.17. Oszlá
Page 32 and 33: Fig. 1. ns-EC to s-EC transition in
Page 34 and 35: Publications Articles F.1. F.2. Bö
Page 36 and 37: G. ELECTRON CRYSTALS G. Kriza, P. M
Page 38 and 39: H. METAL PHYSICS K. Tompa, I. Bakon
Page 40 and 41: thickness can be elucidated by deco
Page 42 and 43: I. METALLURGY AND MAGNETISM L.K. Va
Page 44 and 45: temperature profile increases the s
Page 46 and 47: I.13 Kane * SN, Khinchi * SS, Gercs
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Page 50 and 51: J.3. J.4. J.5. J.6. J.7. Avdeev * M
Page 52 and 53: Macromolecular Compounds (Visokomol
Page 54 and 55: defined coordination sphere was fou
Page 56 and 57: László Temleitner temla@szfki.hu
Page 58 and 59: Book chapter K.22. Temleitner L, Pu
Page 60 and 61: Fig. 1 Characteristics of surface p
Page 62 and 63: M. LASER PHYSICS K. Rózsa, G. Bán
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Publications Articles M.1. Sigenege
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O. LASER APPLICATION A. Czitrovszky
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Raman spectroscopy is widely used f
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Bilateral Austro-Hungarian Cooperat
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P. FEMTOSECOND LASERS R. Szipőcs,
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Grants and international cooperatio
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E-Mail: Kárpát Ferencz optilab@t-
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y optical microscopy. While in Y 2
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Publications: Articles R.1. Földv
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S. CHARACTERIZATION AND POINT DEFEC
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groups of the Li 2 B 4 O 7 lattice.
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S.10. Lengyel K, Kovács L, Péter
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entanglement one has to find method
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T.7. T.8. T.9. Asbóth JK, Domokos
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EDUCATION Graduate and postgraduate
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Laboratory practice and seminars
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G. Dravecz (ELTE and Université de
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⎯ K. Kamarás: Editorial Board Me
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CONFERENCES ⎯ Electrochemistry se
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TABLE of CONTENTS PREFACE 1 KEY FIG
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