Pedro de Andres

Pedro's Picture Welcome. My field of interest is Theoretical Physics and Chemistry (Condensed Matter and Surface Science). I have been working on/with LEED, STM, BEEM, DFT, chemisorption on surfaces, surface electrodynamics, etc.

Scopus: de Andres, Pedro L. (7004863107)
I shall be pleased to hear your comments: do not hesitate to contact me if you need any assistance.

My email can be found by clicking the following link: Correspondence to Pedro de Andres
Instituto de Ciencia de Materiales de Madrid (CSIC)
E-28049 Cantoblanco (Madrid) SPAIN
Tfno: +34 91 334 9049; Mobile: +34 669 633 037; FAX: +34 91 372 0623


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Updated on September, 2014.

  • Curriculum Vitae

  • Recent Publications
  • DOI: 10.1002/chem.201200627; "Weakly interacting molecular layer of spinning C60 molecules on TiO2(110) surfaces"; Chemistry -- A European Journal (in press) (2012).
  • DOI: ; "Spin alignment of extra electrons in K-phenanthrene clusters taken from the cyrstalline tripotassium-intercalated phenanthrene structure"; Phys. Rev. B. (in press) (2012).
  • DOI: 10.1103/PhysRevLett.108.115902; "Diffusion of Hydrogen in Paladium assisted by inelastic Ballistic Hot Electrons"; M. Blanco-Rey, M. Alducin, J.I. Juaristi, P.L. de Andres, Phys. Rev. Lett. 108, 115902 (2012).

  • Research Interests

    You will find information about my research interests and references to some selected recent publications following the link above. You are welcome to contact me anytime for more information.

  • "First-principles calculation of the effects of stress on the chemical activity of graphene", Appl. Phys. Lett. 93, 171915 (2008); DOI:10.1063/1.3010740

    Graphene layers are stable, hard, and relatively inert. We study how tensile stress affects and bonds and the resulting change in the chemical activity. Stress affects more strongly bonds that can become chemically active and bind to adsorbed species more strongly. Upon stretch, single C bonds are activated in a geometry mixing 120 and 90, an intermediate state between sp2 and sp3 bonding. We use ab initio density functional theory to study the adsorption of hydrogen on large clusters and two-dimensional periodic models for graphene. The influence of the exchange-correlation functional on the adsorption energy is discussed. 2008 American Institute of Physics PDF

  • "Strong covalent bonding between two graphene layers", Phys. Rev. B 77, 045403 (2008); DOI:10.1103/PhysRevB.77.045403

    We report on a new type of carbon extended structure formed by two graphene layers stacked directly on top of each other (stacking AA). This polymorphic form of a graphene bi-layer is meta-stable with a distance between planes of 0.156 nm, denoting single covalent carbon-carbon bonding accross the layers. The size of the 2D hexagonal unit cell is streched from 0.243 nm to 0.267 nm length, weakening the $sp^{2}$ in-plane bonds. Depending on the separation between layers, the electronic structure of the bi-layer changes from semi-metal, to metal, to wide-gap semiconductor. We describe the electronic structure of these bi-layers and their behaviour under external anisotropic stresses. Carbon shows one of the richest chemistry in the periodic table and it is often found in allotropic forms. In molecules it is the basis for organic compounds, being central to different fields from biology to electronics in new materials. In solid state it shows very different properties drifting from a soft metal (graphite, the most stable configuration at P=0 GPa, T= 0 K) to a hard wide-gap semiconductor (diamond). New forms like fullerenes and nano-tubes have raised even more the interest in carbon for their potential applications. Recently, the realization of two-dimensional periodic systems made by the stacking of few graphene layers (FGL), going down to the single layer, has attracted much interest as the basis for new electronic devices\cite{novoselov04,berge06}. The peculiar linear dispersion found in the electronic band structure near the charge neutrality point (Dirac Point), where the carriers behave like mass-less chiral relativistic particles, translates in all sort of new phenomena related to transport properties on these systems\cite{heersche07,altland06}. We have found that two graphene layers stack directly on top of each other to make strong covalent bonds at short distances, unlike the standard weak van der Waals interaction between layers in graphite (Fig. 1). This polymorphic form of a graphene bi-layer is meta-stable with a distance between planes of 0.156 nm and a 0.267 nm length for the hexagonal two-dimensional (2D) unit cell ($a=b$, $\gamma=120^{o}$; four carbon atoms). Each carbon in this structure is bonded to the four nearest carbon neighbours, at 0.154 and 0.156 nm for in-plane and out-of-plane bonds respectively. Under these conditions, the bi-layer is a wide gap semiconductor. As a function of the separation between layers, transport properties of the AA stacking are rich: at large distances between planes (e.g., as found in graphite) the system behaves like a low density of states 2D metal or even a semi-metal, being mostly dominated by the single graphene layer properties. As the distance between layers decreases it is possible to find interlayer distances and/or different 2D unit cell sizes where the bi-layer becomes metallic under their own internal stresses, opening a new route to understand and control transport experiments on FGL. These configurations sit in between the meta-stable local energy minimum reported in this paper (Fig. 2, label "A") and the global one (graphite-like, "G"). 2008 American Physical Society PDF

  • "Hydrogen in alpha-iron: Stress and diffusion", Phys. Rev. B 78, 014113 (2008); DOI:10.1103/PhysRevB.78.014113

    First-principles density-functional theory has been used to investigate equilibrium geometries, total energies, and diffusion barriers for H as an interstitial impurity in alpha-Fe. Internal strain/stress upon hydrogen absorption are a crucial factor to understand preferred absorption sites and diffusion. For high concentrations H absorbs near the octahedral site favoring a large tetrahedral distortion in the bcc lattice. Diffusion paths depend on the concentration regime too; hydrogen diffuses about ten times faster in the distorted bct lattice. External stresses of serveral GPa modify barriers by 10% and diffusion rates by 30% 2008 American Physical Society PDF

  • Clare Hall Spanish Society Website

    Clare Hall is a College for Advanced Studies in the University of Cambridge. It hosts scholars and alumni in many different fields and from a wide variety of countries over the world. The President, Prof. E. Salje, has followed and active policy to promote the development of national societies of people related to the college and a group of Spanish scholars and alumni interested in that initiative created in 2005 the Clare Hall Spanish Society. Our goal is to help Spanish people interested to work in the University of Cambridge to find the right environment provided by such a college as Clare Hall. We have been meeting regularly once per year, starting in Madrid (2006), followed by Salamanca (2007) and our next meeting will be in Barcelona (2008). Everyone interested is welcome to come and meet us (more details in the Clare Hall website that you can reach following the link above).

    Estrella Morente canta a la muerte de su padre: ESTRELLA