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Trinity College Dublin

Ongoing Research Projects supported by TCHPC

TCHPC allocates resources to assist research in many different fields. Below is a list of current projects been undertaken with the help of TCHPC.
  • Physics
    Compute
    B
    Professor Igor Shvets
    Trinity College Dublin
    The growth of Fe nanoclusters on the Ge(001) surface has been studied using low-temperature scanning tunneling microscopy (STM), low-energy electron diffraction and x-ray magnetic circular dichroism (XMCD). STM results indicate that Fe nucleates on the Ge(001) surface forming well ordered nanoclusters of an uniform size. Annealing these nanoclusters at moderate temperatures leads to a formation of nanowire-like structures, due to cluster mobility at such temperature. These arrays of Fe nanoclusters show a magnetic response as measured by XMCD.DFT will clarify the inner structure of the Fe nanoclusters and the local charge density will be compared with the acquired STM images.
  • Chemistry
    Storage
    Compute
    A
    Prof. Graeme Watson
    Trinity College Dublin
    Replacement of In2O3:Sn (ITO) as the industry standard n-type transparent conducting oxide (TCO) is a global research goal for materials scientists. Alternative n-type TCOs include ZnO:Al and SnO2:Sb/F, however these materials have not yet yielded conductivities consistent with ITO. In this study we use first principles methods to understand the reasons for the under performances of these alternative TCOs, and attempt to predict alternative pathways to higher performance.
  • Chemistry
    Compute
    A
    Prof. Graeme Watson
    Trinity College Dublin
    Solid oxide fuel cells (SOFCs) are devices which generate electricity from a variety of sources, such as hydrogen or hydrocarbons. This electrolytic conversion can reach efficiencies of up to 85%. Current electrolyte technology used in solid oxide fuel cells requires high operational temperatures which makes them expensive to build and impractical in all but very large scale facilities. Our goal is therefore the study of conductivity in yttrium-doped ceria (Ce1-xYxO2-x/2,) which can be used at intermediate temperature regimes. In this project we seek to rationalize the effect of aliovalent doping on the conductivity of CeO2 using atomistic and ab initio modelling methods, the results of which will be compared with experimental data gathered by Dr Stephen Hull’s group at ISIS in the UK. We have developed an interatomic potential for yttrium-doped ceria from DFT calculations, in collaboration with Prof Paul Madden’s group in Oxford. This potential, which allows for the description of dipole polarizabilites in the species being simulated, will then used in molecular dynamics simulations that can be run for time periods in the nano second scale; this is a clear advantage over full ab initio simulations of the systems in question, which using current hardware make simulations beyond 10ps impractical. Our calculations will allow the determination of properties including ionic conductivity, vacancy formation energies, residence times and structural data, such as the radial distribution function, which are key to our understanding of materials for the next generation of SOFCs.
  • Chemistry
    Storage
    Compute
    A
    Prof. Graeme Watson
    Trinity College Dublin
    The modelling of p-type semiconductors is important in the development of thin-film transistors (TFTs). Expitaxially grown thin films of tin monoxide have been shown to give enhanced performance over previously reported p-type channel oxide TFTs. SnO is a layered material, with strong van der Waals existing between the layers. Although standard DFT methods have been used the model the electronic structure, they fail to accurately model the atomic structure due to van der Waals interactions being neglected in DFT. The aim of this work, therefore, is to investigate the use of van der Waals corrections to enable the correct structural prediction of SnO. This will be studied using not only standard DFT methods, but also using the hybrid HSE06 and PBE0 functionals, which will allow for a more accurate description of the electronic structure.
  • Chemistry
    Storage
    Compute
    A
    Prof. Graeme Watson
    Trinity College Dublin
    In the silver-oxygen system, silver is known to possess both Ag(I) and Ag(III) valence states, this giving rise to a number of different phases. Silver oxides, in particular Ag2O and AgO, have important technological applications including Zn-silver oxide batteries, fast-ion conducting glasses and a range of dermatological uses due to their bacteriostatic properties. However, a full description of the electronic structure of these oxides is lacking in the literature. In addition, all previous computational studies on these materials use a standard GGA functional. This gives rise to the band gaps of these materials being significantly underpredicted. The mixed valence oxide, AgO, also has given rise to controversy in the literature, with studies the Ag valence states to be either an Ag(I,III)O or Ag(I,II)O with synergistic holes on the oxygen atoms. This aim of this study is therefore to fully characterise the electronic structures of the dominant silver oxides, namely Ag2O, AgO and Ag2O3, using hybrid-DFT models. Initial calculations of AgO have already shown conclusively that the correct mixed valence of AgO is Ag(I,III)O. Further to this, GGA is seen to fail to correctly model the mixed valence nature, predicting a symmetric Ag(II)O structure.
  • Computer Science
    Compute
    C
    Prof. Linda Doyle
    Trinity College Dublin
    As part of a study of the real spectrum utilisation in the Dublin area,a series of spectrum measurements have been carried out in the pastmonths. An analysis of the utilisation in both in time and space showshow, when, and where the spectrum could be re-used by cognitive radiosystems, without disturbing existing spectrum users. A statisticalanalysis of the measured spectrum data is performed, detecting usagepatterns and predicting future usage.
  • Life Sciences
    Compute
    A
    Prof. Stefano Sanvito
    Trinity College Dublin
    This project aims at exploring theoretically, by first principles methods, the viability of next generation high-throughput and low-cost DNA squencing protocols utilizing nanopore-based technology. DNA sequencing technology is of fundamental importance to genome research which in turn has a tremendous impact to the development of new medical diagnostics and treatments, molecular medicine, agriculture, evolutionary biology, etc. Nanopore DNA sequencing offers a promising high-throughput and low-cost ”third generation” technology that will be able to sequence a diploid mammalian genome for $1,000 within 24 hours, which will make routine and personal geneitic medical applications feasible and revolutionize genetic medicine. However, theoretical work is needed to answer some fundamental and critical questions at the heart of the technical challenges of nanopore DNA sequencing methods. In this project, by combining Molecular Dynamics simulations, Electronic Structure Theory and Quantum Transport, we will design and build atomic models for various nanopore devices, simulate the electric field-driven translocation of DNA molecules through the pores, analyze the mutual interaction between the DNA and the pores and investigate how the ionic and transverse electrical currents during the DNA translocation can be employed to decode the DNA sequence. Results from this project will provide valuable insights into the mechanism of nanopore sequencing and guidance to device design, thus accelerating the development of such a technology. The proposed investigation represents the theoretical side of a medium-scale European program for nanopores DNA sequencing with partners from Germany, Switzerland, Serbia and Israel (nanoDNAsequencing: NanoTools for Ultra Fast DNA Sequencing; Grant agreement no.: 214840).
  • Chemistry
    Compute
    B
    Trinity College Dublin
    Having constructed a series of synthetic molecular channels that mimic those in biological cell membranes the project investigates the motion of charged species (ions) through them, usually under the influence of an applied electric field. By performing molecular dynamic simulations we consider how details of the migration depend on the sizes, chemical nature and electrostatic charge distributions in the migrating species and in the molecular channel. Quantum chemical calculations are also performed to examine the interactions of the migrant with the host channel.
  • Economics
    Compute
    C
    Gareth Bennett
    Trinity College Dublin
    This paper investigates how the average risk characteristics of a group of international migrants changes over time, and how this dynamic is affected by the changing size of migrant networks in the receiving country. The theoretical model shows that as the size of the migrant network increases, uncertainty is reduced, altering the composition of migrants and the timing of the migration decision. The model provides three main results. Firstly, the average migrant will be more risk averse when more individuals from the source country are present in the receiving country. Secondly, when network effects are stronger all individuals, apart from the most risk loving, will migrate sooner. Thirdly, when network effects are stronger the rate of migration will be greater. Based on these theoretical findings, policy implications for both the sending and receiving country are discussed. This paper will test the theoretical model using data from the American Community Survey.
  • Physics
    Compute
    A
    Prof. Stefano Sanvito
    Trinity College Dublin
    Investigation of the effect of current induced forces on electron-phonon coupling at the metal-molecular-metal junction. This research includes exact evaluation of current induced forces based on first-principles and implementation into exinsting program package. The transport properties are calculated within the formalism of nonequilibrium Green\'s Functions as implemented in the Smeagol code. The density functional theory part of the Smeagol is based on SIESTA package.

Last updated 01 Sep 2014Contact TCHPC: info | support.