Noticias de quienes fueron los del apellido de Cortázar, de su casa solar antigua, pariente maior y cabeza de vando, en Manurga, sita en la Alda de la gran Montaña de Gorbea, y como se entroncaron con Garibay, y los actos, yempleos, que obtubieron [Manuscrito]

Manuscrito sin fechar. Fecha probable S. XVIIAtribuido a J. Olariaga de BergaraDigitalización. Vitoria-Gasteiz : Fundación Sancho el Sabio, 2008Digitalización. Vitoria-Gasteiz : Archivos y Bibliotecas, Junio 1995Holandes

Quadratic electronic response of a two-dimensional electron gas

The electronic response of a two-dimensional (2D) electron system represents a key quantity in discussing one-electron properties of electrons in semiconductor heterojunctions, on the surface of liquid helium and in copper-oxide planes of high-temperature superconductors. We here report an evaluation of the wave-vector and frequency dependent dynamical quadratic density-response function of a 2D electron gas (2DEG), within a self-consistent field approximation. We use this result to find the $Z_1^3$ correction to the stopping power of a 2DEG for charged particles moving at a fixed distance from the plane of the 2D sheet, $Z_1$ being the projectile charge. We reproduce, in the high-density limit, previous full nonlinear calculations of the stopping power of a 2DEG for slow antiprotons, and we go further to calculate the $Z_1^3$ correction to the stopping power of a 2DEG for a wide range of projectile velocities. Our results indicate that linear response calculations are, for all projectile velocities, less reliable in two dimensions than in three dimensions.Comment: 17 pages, 5 figures, to appear in Phys. Rev.

Nesting Induced Peierls-type Instability for Compressed Li-CI16

Alkalies are considered to be simple metals at ambient conditions. However, recently reported theoretical and experimental results have shown an unexpected and intriguing correlation between complex structures and an enhanced superconducting transition temperature in lithium under pressure. In this article we analyze the pressure induced Fermi surface deformation in bcc lithium, and its relation to the observed cI16 structure. According to our calculations, the Fermi surface becomes increasingly anisotropic with pressure and develops an extended nesting along the bcc [121] direction. This nesting induces a phonon instability of both transverse modes at N, so that a Peierls-type mechanism is proposed to explain the stability of Li-cI16.Comment: Proceedings of Fukuoka 2006 Conference on Novel Pressure-induced Phenomena in Condensed Matter Systems. To be published in J. Phys. Soc. Jpn. 2 pages and 3 figure

Noticias de la torre de Garibay, de sus señores, de sus regalías etc. De las casas de Aguirre, Guebara, Galarza, Cortazar, Villela y Mendoza [Manuscrito]

Manuscrito sin fechar. Fecha probable S. XVIIAtribuido a J. de Olariaga de BergaraDigitalización. Vitoria-Gasteiz : Fundación Sancho el Sabio, 2008Digitalización. Vitoria-Gasteiz : Archivos y Bibliotecas, Junio 1995Holandes

["Relación de la casa y torre de Garibay y de su antigüedad y sucesiones que ha habido, junto con los hechos mas destacados. Noticias de oñacinos y gamboinos"] [Manuscrito]

Manuscrito sin fechar. Fecha probable S. XVIITít. facticioIncipit: Garibay. Esta casa, solar y torre de Garibay es en jurisdicción de la villa de Oñate, cassa de pariente mayor del bando gamboinoAtribuido a J. Olariaga de BergaraDigitalización. Vitoria-Gasteiz : Fundación Sancho el Sabio, 2008Digitalización. Vitoria-Gasteiz : Archivos y Bibliotecas, Septiembre 1995Holandes

Time-dependent density-functional theory approach to nonlinear particle-solid interactions in comparison with scattering theory

An explicit expression for the quadratic density-response function of a many-electron system is obtained in the framework of the time-dependent density-functional theory, in terms of the linear and quadratic density-response functions of noninteracting Kohn-Sham electrons and functional derivatives of the time-dependent exchange-correlation potential. This is used to evaluate the quadratic stopping power of a homogeneous electron gas for slow ions, which is demonstrated to be equivalent to that obtained up to second order in the ion charge in the framework of a fully nonlinear scattering approach. Numerical calculations are reported, thereby exploring the range of validity of quadratic-response theory.Comment: 14 pages, 3 figures. To appear in Journal of Physics: Condensed Matte

Prediction of high-Tc superconductivity in ternary lanthanum borohydrides

The study of superconductivity in compressed hydrides is of great interest due to measurements of high critical temperatures (Tc) in the vicinity of room temperature, beginning with the observations of LaH10 at 170-190 GPa. However, the pressures required for synthesis of these high Tc superconducting hydrides currently remain extremely high. Here we show the investigation of crystal structures and superconductivity in the La-B-H system under pressure with particle-swarm intelligence structure searches methods in combination with first-principles calculations. Structures with six stoichiometries, LaBH, LaBH3, LaBH4, LaBH6, LaBH7 and LaBH8, were predicted to become stable under pressure. Remarkably, the hydrogen atoms in LaBH8 were found to bond with B atoms in a manner that is similar to that in H3S. Lattice dynamics calculations indicate that LaBH7 and LaBH8 become dynamically stable at pressures as low as 109.2 and 48.3 GPa, respectively. Moreover, the two phases were predicted to be superconducting with a critical temperature (Tc) of 93 K and 156 K at 110 GPa and 55 GPa, respectively. Our results provide guidance for future experiments targeting new hydride superconductors with both low synthesis pressures and high Tc.Comment: 16 pages, 5 figures

Sources of pro-cyclicality in east Asian financial systems

Procyclicality is a normal feature of economic systems, but financial sector weaknesses can exacerbate it sufficiently to pose a threat to macroeconomic and financial stability. These include shortcomings in bank risk management and governance, in supervision and in terms of dependence on volatile sources of funds. The paper tests econometrically for the importance of such features leading to pro-cyclicality in the financial systems of 11 East Asian countries. This analysis makes it possible to identify specific policy measures for East Asian countries that could limit the extent to which financial systems exacerbate pro-cyclicality

Crystal Structure of SiH4 under Pressure

The crystal structure of a high-pressure phase of silane (SiH4), observed between 10 and 25GPa, is solved using powder synchrotron x-ray diffraction and shown to be of the SnBr4 type. The phase is an insulating molecular solid with a monoclinic unit cell containing four tetrahedrally bonded molecules, space group P21∕c. Ab initio calculations show the SnBr4-type structure to be favored in this pressure range relative to other recently proposed structures. The fit of the pressure dependence of volume to the Birch-Murnagham equation of state gives the following parameters at ambient pressure if K′0 is fixed to 4: V0=250(9)Å3 and K0=7.8(9)GPa for the experimental data, and V0=255(2)Å3 and K0=6.1(2)GPa for the data obtained from ab initio calculations.This work was supported by NSF (DMR, DOE Grant No. DEFG02-02ER4595, and DOE - CDAC). The x-ray measurements were performed at HPCAT Sector 16, Advanced Photon Source APS, Argonne National Laboratory. The HPCAT facility is supported by DOE-BES, DOENNSA - CDAC, NSF, DOD-TACOM, and the W.M. Keck Foundation. The use of the APS was supported by DOE-BES under Contract No. W-31-109-ENG-38. M.M.C. would like to thank the Spanish Ministry of Education and Science for providing a grant. M.M.C. and A.B. acknowledge partial support from the EC sixth Framework Network of Excellence NANOQUANTA NMP4-CT-2004-500198.Peer reviewe