2,300 research outputs found
How have global shocks impacted the real effective exchange rates of individual euro area countries since the euro's creation?
This paper uncovers the response pattern to global shocks of euro area countries' real effective exchange rates before and after the start of Economic and Monetary Union (EMU), a largely open ended question when the euro was created. We apply to that end a newly developed methodology based on high dimensional VAR theory. This approach features a dominant unit to a large set of over 60 countries' real effective exchange rates and is based on the comparison of two estimated systems: one before and one after EMU. We find strong evidence that the pattern of responses depends crucially on the nature of global shocks. In particular, post-EMU responses to global US dollar shocks have become similar to Germany's response before EMU, i.e. to that of the economy that used to issue Europe's most credible legacy currency. By contrast, post-EMU responses of euro area countries to global risk aversion shocks have become similar to those of Italy, Portugal or Spain before EMU, i.e. of economies of the euro area's periphery. Our findings also suggest that the divergence in external competitiveness among euro area countries over the last decade, which is at the core of today's debate on the future of the euro area, is more likely due to country-specific shocks than to global shocks.Euro, Real Effective Exchange Rates, Weak and Strong Cross Sectional Dependence, High-Dimensional VAR, Identification of Shocks.
A Tight-Binding Investigation of the NaxCoO2 Fermi Surface
We perform an orthogonal basis tight binding fit to an LAPW calculation of
paramagnetic NaCoO for several dopings. The optimal position of the
apical oxygen at each doping is resolved, revealing a non-trivial dependence of
the band structure and Fermi surface on oxygen height. We find that the small
e hole pockets are preserved throughout all investigated dopings and
discuss some possible reasons for the lack of experimental evidence for these
Fermi sheets
Precise Tight-binding Description of the Band Structure of MgB2
We present a careful recasting of first-principles band structure
calculations for MgB2 in a non-orthogonal sp-tight-binding (TB) basis. Our TB
results almost exactly reproduce our full potential linearized augmented plane
wave results for the energy bands, the densities of states and the total
energies. Our procedure generates transferable Slater-Koster parameters which
should be useful for other studies of this important material.Comment: REVTEX, 2 Encapsulated PostScript Figure
Origin of Superconductivity in Boron-doped Diamond
Superconductivity of boron-doped diamond, reported recently at T_c=4 K, is
investigated exploiting its electronic and vibrational analogies to MgB2. The
deformation potential of the hole states arising from the C-C bond stretch mode
is 60% larger than the corresponding quantity in MgB2 that drives its high Tc,
leading to very large electron-phonon matrix elements. The calculated coupling
strength \lambda ~ 0.5 leads to T_c in the 5-10 K range and makes phonon
coupling the likely mechanism. Higher doping should increase T_c somewhat, but
effects of three dimensionality primarily on the density of states keep doped
diamond from having a T_c closer to that of MgB2.Comment: Four pages with two embedded figures, corrected fig1. (To appear in
Physical Review Letters(2004)
Tight-binding study of structure and vibrations of amorphous silicon
We present a tight-binding calculation that, for the first time, accurately
describes the structural, vibrational and elastic properties of amorphous
silicon. We compute the interatomic force constants and find an unphysical
feature of the Stillinger-Weber empirical potential that correlates with a much
noted error in the radial distribution function associated with that potential.
We also find that the intrinsic first peak of the radial distribution function
is asymmetric, contrary to usual assumptions made in the analysis of
diffraction data. We use our results for the normal mode frequencies and
polarization vectors to obtain the zero-point broadening effect on the radial
distribution function, enabling us to directly compare theory and a high
resolution x-ray diffraction experiment
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