Search or filter publications

Filter by type:

Filter by publication type

Filter by year:

to

Results

  • Showing results for:
  • Reset all filters

Search results

  • Journal article
    Ahmad EA, Mallia G, Kramer D, Tileli V, Kucernak AR, Harrison NMet al., 2012,

    Comment on "2D Atomic Mapping of Oxidation States in Transition Metal Oxides by Scanning Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy"

    , PHYSICAL REVIEW LETTERS, Vol: 108, ISSN: 0031-9007
  • Journal article
    Ferretti A, Mallia G, Martin-Samos L, Bussi G, Ruini A, Montanari B, Harrison NMet al., 2012,

    <i>Ab initio</i> complex band structure of conjugated polymers: Effects of hydrid density functional theory and <i>GW</i> schemes

    , PHYSICAL REVIEW B, Vol: 85, ISSN: 2469-9950
  • Journal article
    Barreto J, Cease H, Diehl HT, Estrada J, Flaugher B, Harrison N, Jones J, Kilminster B, Molina J, Smith J, Schwarz T, Sonnenschein Aet al., 2012,

    Direct search for low mass dark matter particles with CCDs

    , PHYSICS LETTERS B, Vol: 711, Pages: 264-269, ISSN: 0370-2693
    • Cite
    • Citations: 87
  • Journal article
    Liborio L, Chew SC, Harrison N, 2012,

    Atomic structure of the (001) surface of CuGaSe<sub>2</sub>

    , SURFACE SCIENCE, Vol: 606, Pages: 496-504, ISSN: 0039-6028
  • Conference paper
    Bernasconi L, Webster R, Tomic S, Harrison NMet al., 2012,

    Optical response of extended systems from time-dependent Hartree-Fock and time-dependent density-functional theory

    , 3rd Workshop on Theory, Modelling and Computational Methods for Semiconductor Materials and Nanostructures (TMCS), Publisher: IOP PUBLISHING LTD, ISSN: 1742-6588
  • Conference paper
    Risplendi F, Cicero G, Mallia G, Bernasconi L, Harrison Net al., 2012,

    A quantum-mechanical study of ZnO and TiO2 based DSC

    , APS March Meeting 2012, Publisher: American Physical Society

    Since the pioneering work of Graetzel, Dye Sensitized Cells (DSCs) have attracted great attention as cheap and effective solar power devices based on wide bandgap metal oxide electrode. Optimization of the DSC is a challenging task as it is a highly complex interacting molecular system. Surface properties of the metal-oxide and proper sensitization with dyes may strongly affect the efficiency. Optimizated DSCs based on TiO2 photoanodes and organic dye have reached conversion efficiency of about 10{\%} whereas the efficiency of ZnO based DSC has been found to be much lower, although this material has photochemical properties similar to TiO2, in general due to the nature of the binding between sensitizer and semiconductor. For this reason understanding how anchoring groups interact with the metal-oxide is fundamental to shed light on the different behaviour of these materials in DSC. Aim of this work is to address the binding of small organic sensitizers, such as catechol and isonicotinic acid molecules, to TiO2 and ZnO surfaces, in terms of geometry, stability, electronic structure and absorption properties. To this end, we employed quantum-mechanical simulations based on hybrid DFT and hybrid TDDFT.
  • Conference paper
    Wu W, Fisher AJ, Harrison NM, Wang H, Wu Z, Gardener J, Heutz S, Jones T, Aeppli Get al., 2012,

    Theoretical modeling of the electronic structure and exchange interactions in Cu(II)Pc

    , International Conference on Strongly Correlated Electron Systems (SCES), Publisher: IOP PUBLISHING LTD, ISSN: 1742-6588
  • Journal article
    Ahmad EA, Liborio L, Kramer D, Mallia G, Kucernak AR, Harrison NMet al., 2011,

    Thermodynamic stability of LaMnO<sub>3</sub> and its competing oxides: A hybrid density functional study of an alkaline fuel cell catalyst

    , PHYSICAL REVIEW B, Vol: 84, ISSN: 2469-9950
  • Journal article
    Wu W, Fisher AJ, Harrison NM, 2011,

    Theoretical modeling of the electronic structure and exchange interactions in a Cu(II)Pc one-dimensional chain

    , PHYSICAL REVIEW B, Vol: 84, ISSN: 2469-9950
    • Cite
    • Citations: 23
  • Journal article
    Bush IJ, Tomic S, Searle BG, Mallia G, Bailey CL, Montanari B, Bernasconi L, Carr JM, Harrison NMet al., 2011,

    Parallel implementation of the <i>ab initio</i> CRYSTAL program: electronic structure calculations for periodic systems

    , PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 467, Pages: 2112-2126, ISSN: 1364-5021
    • Cite
    • Citations: 33
  • Journal article
    Bernasconi L, Tomic S, Ferrero M, Rerat M, Orlando R, Dovesi R, Harrison NMet al., 2011,

    First-principles optical response of semiconductors and oxide materials

    , PHYSICAL REVIEW B, Vol: 83, ISSN: 1098-0121
  • Journal article
    Scaranto J, Mallia G, Harrison NM, 2011,

    An efficient method for computing the binding energy of an adsorbed molecule within a periodic approach. The application to vinyl fluoride at rutile TiO<sub>2</sub>(110) surface

    , COMPUTATIONAL MATERIALS SCIENCE, Vol: 50, Pages: 2080-2086, ISSN: 0927-0256
    • Cite
    • Citations: 49
  • Journal article
    Liborio LM, Bailey CL, Mallia G, Tomic S, Harrison NMet al., 2011,

    Chemistry of defect induced photoluminescence in chalcopyrites: The case of CuAlS<sub>2</sub>

    , JOURNAL OF APPLIED PHYSICS, Vol: 109, ISSN: 0021-8979
  • Journal article
    Martinez-Casado R, Mallia G, Usvyat D, Maschio L, Casassa S, Schuetz M, Harrison NMet al., 2011,

    Periodic quantum mechanical simulation of the He-MgO(100) interaction potential

    , JOURNAL OF CHEMICAL PHYSICS, Vol: 134, ISSN: 0021-9606
  • Journal article
    Martinez-Casado R, Mallia G, Harrison NM, 2011,

    An alternative approach for the calculation of correlation energy in periodic systems: a hybrid MP2(B3LYP) study of the He-MgO(100) interaction

    , CHEMICAL COMMUNICATIONS, Vol: 47, Pages: 4385-4387, ISSN: 1359-7345
  • Conference paper
    Patel M, Mallia G, Liborio L, Harrison NMet al., 2011,

    A Hybrid Density Functional Study of Water Adsorption on Rutile TiO2(110) for Applications in Solar Hydrogen Production

    , http://www.nsti.org/procs/Nanotech2011v1/9/W3.183, Nanotech 2011, Publisher: NSTI

    Theoretical and experimental methods are adopted in order to gain further understanding of photocatalytic water splitting over the semiconductor TiO2. Periodic density functional theory calculations are used to study the adsorption of water on the rutile TiO2(110) surface. Results of studying the influence of acidic surface species on the energetics of the system are compared with new experimental measurements of the kinetics (using transient absorption spectroscopy) and photocurrent (photoelectrochemical set-up) as a function of pH.
  • Journal article
    Martinez-Casado R, Mallia G, Usvyat D, Maschio L, Casassa S, Schuetz M, Harrison NMet al., 2011,

    He-atom scattering from MgO(100): calculating diffraction peak intensities with a semi <i>ab initio</i> potential

    , PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 13, Pages: 14750-14757, ISSN: 1463-9076
  • Journal article
    Martinez-Casado R, Mallia G, Harrison NM, 2011,

    <i>Ab initio</i> calculation of the MgO(100) interaction with He and Ne: a HF+MP2 and HF+MP2(B3LYP) comparison

    , CHEMICAL COMMUNICATIONS, Vol: 47, Pages: 11630-11632, ISSN: 1359-7345
  • Journal article
    De Fusco GC, Montanari B, Harrison NM, 2010,

    Half-metallicity in the ferrimagnet Nb(TCNE)<sub>2</sub> from first principles

    , PHYSICAL REVIEW B, Vol: 82, ISSN: 1098-0121
  • Journal article
    Virk N, Montanari B, Harrison NM, 2010,

    Ab-initio investigation of graphane

    , Nanotechnology 2010 Advanced Materials Cnts Particles Films and Composites Technical Proceedings of the 2010 Nsti Nanotechnology Conference and Expo Nsti Nanotech 2010, Vol: 1, Pages: 296-299

    First-principles calculations employing the hybrid exchange functional B3LYP are used to determine the structural parameters, electronic structure and associated properties of a graphene sheet, graphane chair and graphane boat confirmations. Graphane is found to have a band gap corresponding to an electronic insulator at room temperature. The relative performance of the B3LYP functional in comparison to calculations employing generalized gradient approximations (PBE) is also assessed. The B3LYP functional finds the band gap to be almost double that predicted by PBE methods. The choice of functional is found to be insignificant in the determination of the structural parameters.
  • Journal article
    Kaur R, Mallia G, Harrison NM, 2010,

    A hybrid exchange density functional study of CrO2 as a spin polarised material for spintronics

    , Nanotechnology 2010 Electronics Devices Fabrication MEMS Fluidics and Computational Technical Proceedings of the 2010 Nsti Nanotechnology Conference and Expo Nsti Nanotech 2010, Vol: 2, Pages: 613-616

    Hybrid exchange density functional theory calculations have been carried out to investigate the effects of strain due to a distortion of the lattice parameter(s) on the electronic properties of CrO<inf>2</inf>, a half metallic ferromagnet. The variation in the density of states near the Fermi level for the majority spin states and the bandgap in the minority spin channel are reported. Understanding such variations is vital to study interface properties of heterostructures based on CrO<inf>2</inf>.
  • Book chapter
    Bailey CL, Mukhopadhyay S, Wander A, Searle B, Harrison Net al., 2010,

    Predictive Modelling of Aluminium Fluoride Surfaces

    , Functionalized Inorganic Fluorides, Editors: Tressaud, Publisher: Wiley, ISBN: 9780470740507
  • Journal article
    Bailey CL, Liborio L, Mallia G, Tomic S, Harrison NMet al., 2010,

    Defect physics of CuGaS<sub>2</sub>

    , PHYSICAL REVIEW B, Vol: 81, ISSN: 2469-9950
  • Report
    Bailey CL, Wander A, Searle BG, Harrison NMet al., 2010,

    Implementation of Nudged Elastic Band in CRYSTAL

    , Dl Technical Report, Publisher: STFC Daresbury Laboratory, DL-TR-2005-003
  • Journal article
    Busayaporn W, Torrelles X, Wander A, Tomic S, Ernst A, Montanari B, Harrison NM, Bikondoa O, Joumard I, Zegenhagen J, Cabailh G, Thornton G, Lindsay Ret al., 2010,

    Geometric structure of TiO<sub>2</sub>(110)(1X1): Confirming experimental conclusions

    , PHYSICAL REVIEW B, Vol: 81, ISSN: 1098-0121
  • Journal article
    Bailey CL, Liborio L, Mallia G, Tomić S, Harrison NMet al., 2010,

    Calculating charged defects using CRYSTAL

    , Journal of Physics Conference Series, Vol: 242, ISSN: 1742-6588

    The methodology for the calculation of charged defects using the CRYSTAL program is discussed. Two example calculations are used to illustrate the methodology: He<sup>+</sup> ions in a vacuum and two intrinsic charged defects, Cu vacancies and Ga substitution for Cu, in the chalcopyrite CuGaS<inf>2</inf>. © 2010 IOP Publishing Ltd.
  • Conference paper
    Harrison N, Chang ITH, 2010,

    Consolidation of elemental aluminium powders using equal channel angular pressing (ECAP)

    The aim is to optimise the consolidation of elemental aluminium powder particles by analysing the effect of different powder sizes on apparent density of powders, density of cold compacted samples and density of ECAP samples. Three different sizes (<45μm, 75-105μm, >150μm) of aluminium powders were conventionally compacted at room temperature (400MPa) for comparison and consolidated in a single pass of ECAP at 200°C (400MPa). Grain size distributions show a significant shift to more refined grain sizes following a single pass of ECAP and better bonding of powder particles. The medium and coarse powder particles achieved the highest density but the fine powder particles showed the smallest grain sizes and highest hardness values.
  • Conference paper
    Kaur R, Mallia G, Yates KA, Harrison NMet al., 2010,

    Computer Simulations of CrO2 as a Spin Polarized Material for Spintronics

    , http://www.nsti.org/procs/Nanotech2010v2/10/T30.102, Nanotech 2010, Publisher: NSTI, Pages: 613-616

    Despite theoretical predictions of chromium dioxide being a half-metallic ferromagnet. Devices based on chromium dioxide have performed poorly. One major issue is the influence of defects on the electronic structure and magnetic properties as well as variations of these properties at surfaces and interfaces. The primary objective of this research is to model point defects in bulk chromium dioxide and at the surface. Here, hybrid density functional theory calculations are used to investigate two point defect candidates: oxygen vacancies and chromium interstitials. The results of this research will be discussed and compared with Yates surface data of chromium dioxide.
  • Conference paper
    Montanari B, Harrison NM, 2010,

    Spin Dependent Transport in Carbon Nanostructures

    , http://www.nsti.org/procs/Nanotech2010v1/2/W21.303, Nanotech 2010, Publisher: NSTI, Pages: 211-214

    A theoretical investigation of the electronic and magnetic structure in carbon nanoribbons, defective graphene and carbon peapod structures. The critical importance of electron correlation in the emergent behaviour will be demonstrated for; the generation of long range magnetic interactions, spin dependent transport and the localisation of well defined spin qubits.
  • Conference paper
    Chew S, Liborio L, Harrison NM, 2010,

    An Ab Initio Study of CuGaSe2 (001) Surface

    , Nanotech 2010, Publisher: NSTI, Pages: 689-692

    The chalcopyrite material CuIn1-xGaxSe2 makes one of the best performing devices for thin film solar cells. Despite this, there is still a lack of understanding of some of the fundamental properties of the material. CuGaSe2 based solar cells show only an efficiency of 9.5%, approximately half the efficiency of Cu(In,Ga)Se2 based solar cells. It is important to investigate surface and bulk properties of the material, and its defect states to improve solar cell efficiency. The study will begin by investigating the CuGaSe2 (001) polar surface under a variety of growth conditions by ab initio theoretical studies. Experimental studies on this surface have already been done (Deniozou et al., 2005a, Deniozou et al., 2005b), and LEED characterization of the surface shows clear (4x1) reconstruction without faceting for CuGaSe2 grown under moderate Cu-excess conditions. The sample grown under low Cu-excess conditions exhibits steps/facets, and the sample at higher Cu-excess exhibits weaker reconstruction. Our study will complement the above experimental investigations by identifying the stable surface structures of the CuGaSe2 (001) reconstruction, and analyzing their surface states and resonance. Total energy electronic structure calculations based on the implementation of Density Functional Theory (DFT) in the CRYSTAL code (http://www.crystal.unito.it/) will be used.

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://www.imperial.ac.uk:80/respub/WEB-INF/jsp/search-t4-html.jsp Request URI: /respub/WEB-INF/jsp/search-t4-html.jsp Query String: id=613&limit=30&resgrpMemberPubs=true&resgrpMemberPubs=true&page=5&respub-action=search.html Current Millis: 1765576208266 Current Time: Fri Dec 12 21:50:08 GMT 2025

Computational Materials Science

Computational Materials Science