Keynote Talks

Confirmed keynote speakers/talks:

  • Dr Gabor Csanyi, University of Cambridge, UK

    Fitting ab initio potential energy surfaces: a systematic approach

    The total energy of most atomistic systems can be decomposed into a sum of analytic and local terms. I will show how to approximate the total energy by systematic expansions, giving rise to interatomic potentials that closely approach the Born-Oppenheimer potential energy surface. 


  • Professor Bill Curtin, EPFL, Switzerland

    X-Mechanics for Metal Plasticity

    The application of X-Mechanics (X=quantum, atomistic, statistical, dislocation, mesoscale, and continuum) to elucidate the mechanistic origins of plasticity phenomena is emerging as a powerful paradigm for predictive metallurgy.  In particular, the structure of dislocations and the interactions of dislocations with solutes, precipitates, other dislocations, and grain boundaries, requires application of X-Mechanics for both qualitative and quantitative models of plastic flow as a function of alloying, temperature, strain-rate, grain size, and including size effects in plasticity.  Here, we show how the X-Mechanics toolbox is being applied to Mg, the lightest structural metal, to predict the controlling deformation mechanisms and effects of alloying.   First, we use first-principles density-functional theory (DFT) to compute the dislocation core structures for basal <a> , pyramidal <c+a>, and twin slip.  Second, we introduce a new interatomic potential for Mg that predicts dislocation core structures and other material properties in good agreement with DFT and/or experiments.  Third, we use the new potential in Molecular Dynamics to show the unusual but critical transformation of the <c+a> dislocation that limits the ductility of Mg.  Fourth, we develop predictive models for yield stress of basal slip and twinning due to solute strengthening to predict strengthening of basal slip and twinning, which serve as a basis for future studies aimed at preventing the detrimental <c+a> transformation.  Additional work on models for twin growth in Mg and Mg solid solution alloys and for Mg fracture are not be discussed here.  This application to Mg, and other recent examples, show the power of X-Mechanics in materials science, and establish it as an integrated approach to achieve predictive computational materials design.


  • Professor Giulia Galli, University of Chicago, USA

    Engineering materials for sustainable energy sources

    Climate change and the related need for sustainable energy sources replacing fossil fuels are pressing societal problems. The development of advanced materials is widely recognized as one of the key elements for new technologies that are required to achieve a sustainable environment and provide clean and adequate energy for our planet. We discuss how the combination of advanced theory and computation, in close connection with state-of-the-art experiments, may lead to successful bottom up design of materials for energy applications.


  • Professor Daan Frenkel, University of Cambridge, UK

    Numerical design of pathways for addressable self-assembly

    A holy grail of nano-technology is to create truly complex, multi-component structures by self assembly.  Most self-assembly has focused on the creation of `structural complexity'. In my talk, I will discuss `Addressable Complexity': the creation of structures that contain hundreds or thousands of distinct building blocks that all have to find their place in a 3D structure.  Recent experiments have demonstrated the feasibility of making such structures.  Simulation and theory yield surprising insights that can inform the design of novel structures and materials. 


  • Dr Gerhard Hummer, Max Planck Institute of Biophysics, Germany

    Molecular simulation of protein dynamics and function

    We use molecular simulations to study functional protein dynamics over a broad range of time scales.  Quantum-mechanics/molecular mechanics (QM/MM) descriptions allow us to follow fast, photoexcitation-driven protein motions on the picosecond scale.  The resulting simulation trajectories are compared directly to femtosecond time-resolved protein crystallography experiments at X-ray free electron lasers.  To study the functional dynamics in molecular motors and pumps  on the nano- to millisecond time scales, we have used classical and QM/MM simulations.  In nonequilibrium simulations, we drive these biomolecular machines by applying mechanical bias and inducing redox transitions that mimic their operation in a biological setting. The simulations help elucidate the molecular mechanisms underlying the efficient energy transduction processes in FoF1-ATP synthase and the proton pump complex I.


  • Professor Nicola Marzari, EPFL, Switzerland

    The Agony and the Ecstasy of Density-functional Theory

    Materials' simulations based on density-functional theory (DFT) have become an extremely powerful and widely used tool for scientific discovery and technological advancement, heralding nowadays a soft revolution in the computational design and discovery of novel materials.

    Still, in the current approximations, they remain an imperfect tool for predicting materials' properties, with open and urgent challenges in the quest for qualitative and quantitative accuracy.

    Several of these challenges stem from a foundational limit - namely of dealing with a functional theory of the total electronic density.

    As such, DFT is unable to predict even in principle single-particle energy levels, and it is forced to devise energy functionals that aim at accuracy while remaining, in a single-particle picture, gloriously unaware of what the true energy levels should be (the highest-occupied one being the exception, at least in exact DFT).

    I'll argue that some of the efforts to improve upon this picture fall into a common class of functionals (extended Hubbard, hybrid, range-separated, Koopmans' compliant) that point to beyond-DFT formulations where both total energies and spectroscopic properties can be accounted for. Such framework will be illustrated with applications to real systems and with exactly-solvable models.

  • Professor Kristin Persson, Lawrence Berkeley National Laboratory, USA

    The Materials Project for Accelerated Design of Novel Materials and Liquids for Energy Harvesting and Storage

    The Materials Genome Initiative (MGI) aims to develop an infrastructure to discover, develop, manufacture, and deploy advanced materials at least twice as fast as possible today, at a fraction of the cost. In this talk I will highlight the advances and development of the Materials Project (www.materialsproject.org), which is an MGI-funded effort to compute the properties of all known inorganic materials and beyond, design novel materials and offer data to the community together with online analysis and design algorithms.1 The current release contains data derived from density functional theory (DFT) calculations for over 60,000 materials, each with searchable associated properties such as relaxed structure, electronic state, energy storage capability, aqueous and solid stability, and more.  The software infrastructure enables thousands of calculations per week – enabling screening and predictions - for both novel solid as well as molecular species with target properties. To exemplify the approach of first-principles high-throughput materials design, we will make a deep dive into some of the ongoing work, showcasing the rapid iteration between ideas, computations, and insight as enabled by the Materials Project infrastructure and computing resources. Novel materials design rules and derived classes in the general areas of photocatalysis, thermoelectrics, beyond-Li energy storage, and alloy design will be presented and discussed.



  • Professor Mark Sansom, University of Oxford

    Molecular Simulations of Complex Biomembranes

    The interactions of membrane proteins with their lipid bilayer environment play a key role in many aspects of their function. However, most structures are determined with at best a few lipid or detergent molecules bound. Molecular simulations can be used to 'transplant' a membrane protein back to a lipid bilayer, thus providing a first approximation to its cellular environment. Using an in silico in vitro approach, one can insert a membrane protein into a single lipid species bilayer, thus mimicking in vitro reconstitution. Such simulations can reveal bound lipid molecules and lipid annuli around membrane proteins. We have developed an automated pipeline, yielding a database of all known membrane protein structures embedded in a simple (PC) lipid bilayer [1]. This is available online via MemProtMD (http://sbcb.bioch.ox.ac.uk/memprotmd/). Cell membranes are complex and crowded, with multiple lipid species and proteins making up 25-50 % of the membrane area. We have developed simulation methods to model this environment [2], thus providing an in silico in vivo approach. I will review recent results on protein/lipid and protein/protein interactions in crowded and complex membranes, including bacterial outer membrane proteins [3], GPCRs, and Kir ion channels.

    References

    1.    Stansfeld, P.J., Goose, J.E., Caffrey, M., Carpenter, E.P., Parker, J.L., Newstead, N. & Sansom, M.S.P. (2015) MemProtMD: automated insertion of membrane protein structures into explicit lipid membranes. Structure 23:1350-1361

    2.    Koldsø, H., Shorthouse, D., Hélie, J , & Sansom, M.S.P. (2014) Lipid clustering correlates with membrane curvature as revealed by molecular simulations of complex lipid bilayers. PLoS Comp. Biol. 10: e1003911

    3.    Rassam, P., Copeland, N.A., Birkholz, O., Tóth, C., Chavent, M., Duncan, A.L., Cross, S.J., Housden, N.G., Seger, U., Quinn, D.M., Garrod, T.J., Sansom, M.S.P. Piehler, J., Baumann, C.G., & Kleanthous, C. (2015) Supramolecular assemblies underpin turnover of outer membrane proteins in bacteria. Nature 523:333–336.

 

  • Professor Nicola Spaldin, ETH, Switzerland

    From Multiferroics to Cosmology with Electronic Structure Calculations 

    What happened in the early universe just after the Big Bang? This is one of the most intriguing basic questions in all of science, but it is extraordinarily difficult to answer because of insurmountable issues associated with replaying the Big Bang in the laboratory. One route to the answer -- which lies at the intersection between cosmology and materials physics -- is to use laboratory materials to test the so-called "Kibble-Zurek" scaling laws proposed for the formation of defects such as cosmic strings in the early universe. Here I will show that a popular multiferroic transition metal oxide -- with its coexisting magnetic, ferroelectric and structural phase transitions -- generates the crystallographic equivalent of cosmic strings. I will describe density functional calculations for the material allow the important features of its behavior to be identified and quantified, and present experimental results of the first unambiguous demonstration of Kibble-Zurek scaling in real materials.

 

  • Professor David Srolovitz, University of Pennsylvania

    Grand Unified Theory of Grain Boundaries 

    Grain boundaries do it all. They transmit stresses, they move under the action of an applied stress, they migrate when curved, they slide, they roughen, they transmit/absorb/emit dislocations,…  They behave differently at low temperature and high temperature, with different grain misorientations, with different inclinations,… I will present a bicrystallography-based model of grain boundaries that rationalizes much of the known grain boundary property phenomenology within a single coherent picture. The ultimate goal is, to quote Albert Einstein, “to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience” (often quoted as “everything should be as simple as possible, but no simpler”). Like the other grand unified theory, we’re getting closer, but...


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