Research Projects
Below is a selection of projects that are representative of the type of research opportunities available in the Computational Materials Science REU. Projects can be found in three main research areas: surface science, biomaterials, and nanoscience. All projects will involve collaboration, using cyberspace-enabled tools, with multiple groups at the four universities participating in the REU.
Computational surface science including thin-film growth and catalysis
T. Rahman, S. Stolbov, and A. Kara - UCF PhysicsComputational surface science uses a variety of approaches including molecular dynamics (MD), density-functional theory (DFT), and kinetic Monte-Carlo (KMC) to elucidate reactions and molecular transport at surfaces. We will offer projects on both thin-film growth and heterogeneous catalysis. Understanding and controlling thin-film growth processes is one of the grand challenge projects. The significance of the research is that it offers the possibility of materials by design. In the case of epitaxial growth, deposited atoms diffuse on the surface before being trapped or attached to others. The details of the morphological evolution of the film depend on the local surface geometry and electronic structure. Students will learn by using empirical potentials to elucidate the microscopic energetics of surface diffusion. The kinetics can be simulated using a combination of MD, molecular-statics (MS), and KMC to examine the evolution and growth of the film. We will focus on low Miller index surfaces of Cu, Ag, and Ir, targeting cases of homo- and hetero-epitaxy to make contact with experimental data. Activation energies will be calculated and used in standard KMC and our recently-developed self-learning KMC. Another focus area is heterogeneous catalysis. The emerging hydrogen economy has generated enormous interest in novel catalysts for hydrogen production, hydrogen oxidation, and oxygen reduction. We will use DFT simulation to predict the catalytic properties of nanostructured catalysts. We will focus on CO oxidation at Au, Pt, and Pt-Ru alloy nanoparticles on oxide surfaces, including ceria, titania, and silica. Recent experimental results from Prof. Beatriz Roldan-Cuenya at UCF have demonstrated strong dependence on the reducibility of the oxide support, although the mechanisms are not well understood. REU students will interact with Prof. Roldan-Cuenya and her students and postdocs through meetings and lab tours. The computational REU students will see firsthand the interaction of theory and experiment. The surface science group works closely together with a mix of undergraduate and graduate students.
Simulation of materials microstructure under reactor environment
A. El-Azab - FSU Department of Scientific Computing and Materials Science ProgramT. Hochrainer - FSU Department of Scientific Computing
Nuclear energy is an important part of our nation's energy portfolio. The successful and safe operation of nuclear reactors relies on the availability of materials that withstand the aggressive environment of nuclear reactor cores. Intense neutron irradiation induces atomic scale damage in the core materials and alters their properties. At Florida State University, the Materials Theory Group is developing computational modeling solutions to this problem, ranging from atomic scale investigation of the nature of the induced materials defects and their evolution and changes in the materials microstructure. Incoming REU students will work closely with Dr. El-Azab and doctoral students on various mathematical and computational aspects of radiation effects in materials. Specifically, the REU students will learn how the reactor environment affects materials at the microscopic level and how the materials defects rearrange at the mesoscale in ways that lead to materials degradation. The students will also participate in research using molecular dynamics models of defect interactions in materials and phase field theory of microstructure changes.
Modeling and Simulation of the cellular microstructures
X. Wang - FSU Department of Scientific ComputingLipids, known as fat, are ubiquitous in biological systems. Most part of cell membrane is composed by lipids with a bilayer structure. It is well known that the efficiency of cellular microstructures. Because the special properties of the lipids, cells have different shapes corresponding to their functions. For example, the surface of the epithelial cells lining our gut contains small, fingerlike extensions of membrane which increases by 20 times the surface area that the epithelial cell can use to absorb nutrients from the gut. Besides the cell membranes, some other microstructures such as the chloroplasts also have highly folded membranes. Simulating those structures, visualizing their shapes and quantitatively measuring their surface area and volume are very important topics in biology research. Incoming REU students will work closely with Dr. Wang and doctoral students to design mathematical models, coding with existing code, perform the numerical simulations, and interpret and visualize results.
Multi-scale modeling of self-assembled surfactant systems
D. Kopelevich - UF Chemical Engineering
Surfactants (or amphiphiles) are molecules that contain both hydrophobic
and hydrophilic segments. In aqueous solutions surfactants spontaneously
self-assemble into a variety of microstructures that find use in
numerous applications, including drug delivery vehicles, fluids with
externally controlled rheological properties, and templates for advanced
nanostructured materials. In addition to their industrial uses,
self-assembled structures of amphiphilic molecules, such as lipid
bilayers, are building blocks for various biological systems. In all of
these systems, the dynamics of self-assembly and transitions between
different self-assembled structures plays an important role. Theoretical
and computational modeling of these processes is extremely challenging
due to a large span of length- and time-scales involved. We
are developing a multi-scale approach to investigation of dynamics of
self-assembled structures. This approach will permit investigation of complex
amphiphilic systems over large length- and time-scales while maintaining
all pertinent molecular-scale information. REU students
participating in this project will learn methods of molecular dynamics
simulations and will be introduced to theoretical tools employed in
development of the multi-scale methods.
Complex metal boro-hydride hydrogen storage materials
V. Bhethanabotla - USF Chemical EngineeringAdvanced complex boro-hydrides that are light-weight, low-cost and have high hydrogen storage capacity are very desirable for on-board vehicular applications. Boro-hydride complexes as hydrogen storage materials have recently attracted great interest as they exceed the 2010 DOE target for hydrogen storage. These materials are the focus of this research. Designing efficient complex boro-hydride materials requires both experimental studies and modeling across different length and time scales. Working closely with Ph.D. student Mr. Pabitra Choudhury, the REU student will utilize a direct method lattice dynamics approach using ab initio force constants to calculate the phonon dispersion curves for several complex boro-hydrides to establish stability of the crystal structures at finite temperatures. He/she will use density functional theory (DFT) to calculate electronic structures and the ab initio force constants for the direct method lattice dynamics calculations. These computational simulations will be utilized in understanding the crystal structure, nature of bonding in complex boro-hydrides, and mechanistic studies on catalytic doping to improve the kinetics and reversibility, and the hydrogen dynamics, with the objective of lowering the decomposition temperature. Since a combined theoretical and experimental approach can better lead us to designing a suitable complex material for hydrogen storage, the REU student will work closely with experimentalists in the group who synthesize, dope and characterize these materials.
Quantum mechanical modeling of single molecule nanodevices
I. Oleynik - USF PhysicsThis project aims at a quantum mechanical investigation of electron and spin transport through single organic molecular devices as well as their relationship to the atomic and electronic properties. A REU student will study atomic and electronic properties of the molecular switch that exhibits hysteresis in the current-voltage (I-V) curve. This switching has been recently observed in a series of experiments but fundamental mechanisms of this unusual behavior are currently unknown. First-principles density- functional calculations (DFT) will be performed to investigate the atomic and electronic properties of bipyridyl-dinitro oligophenylene-ethylene dithiol (BPDN) molecular devices. Both neutral and positively and negatively charged molecules will be considered. The REU students will also screen several other classes of molecules to determine the existence of two different molecular conformations: one for a neutral molecule and another for a negative molecular ion. Based on this knowledge, two modes of hysteresis behavior: the polaron and exciton mechanisms of conductance hysteresis will be thoroughly investigated. In addition, phenomenon of the Coulomb blockade will also be considered. The major focus will be on establishing the structure- property relationship: how the chemical structure of different functional groups affects the switching behavior of these molecular switches.
Electronic properties of carbon nanotubes
L.M. Woods - USF PhysicsCarbon nanotubes have drawn much interest due to their unique structure and electronic properties as well as their potential applications in developing different devices, such as energy storage elements, functionalized structures, sensors, biocompatible agents, bearing devices, etc. Carbon nanotubes are seamless rolled graphite sheets, which can be metallic or semiconducting depending on the way the rolling is done. Of particular importance is the ability of nanotubes to interact with different materials. In fact, this ability is in the basis of the majority of envisioned devices involving nanotubes. In this study, the main focus will be to investigate the adsorption properties of carbon nanotubes to different DNA building blocks, such as adenine, guanine, cytosine, and thymine. This is motivated by the increasing role of carbon nanotubes in the biological fields. In addition, the role of different imperfections, such as deformations and defects, in the adsorption process will also be studied. The studies will be performed using state of the art density functional theory (DFT) methods, using computer codes such as VASP and Abinit, which are available at the USF computing facilities. The students will also learn how to model realistic nanostructured systems within DFT methods and extract necessary data from the simulations. In addition, undergraduates will be exposed to large scale computing systems and gather experience how to use them for simulating materials properties.
Ferroic Materials at Nanoscale
I. Ponomareva - USF PhysicsOne very exciting class of materials is that of ferroics. Ferroic is a rather generic term that is used for materials that develop some properties spontaneously (without external influence). Traditional examples include ferroelectric (spontaneous electric dipole moment), ferromagnetic (spontaneous magnetization), ferroelastic (spontaneous strain) materials. Such materials are at the heart of numerous devices ranging from lighter to computer memory, including such revolutionary technologies as ultrasound imaging and night-vision devices. It is no surprise that they have been captivating scientific minds for many years. Thanks to that our current knowledge about these materials is quite satisfactory. But there is one mystery about them: What happens at nanoscale? In our group we design and conduct state-of-the-art computational experiments to answer this question. We bring together the unique capabilities of precise atomistic modeling and power of supercomputers to explore the mind boggling dimensions, sizes, properties, phenomena, and processes to uncover the "megaworld'' of possibilities in "nanoworld'' of tiny matter. The REU student will work towards understanding the ferroic materials at nanoscale.
Project 1: Computational exploration of multiferroic nanowires. Multiferroic materials combine more than one ferroic property and hold tremendous technological potential. In this project the REU student will conduct computer simulations to identify how the properties of such materials change at nanoscale.
Project 2: Electrocaloric properties of ferroelectric nanowires. Electrocaloric effect is associated with a reversible change in the temperature under application or removal of electric field and has tremendous potential for solid-state refrigeration. The REU student will conduct simulations to calculate the effect in ferroelectric nanowires in order to identify how it depends on the size and dimensionality.
Thermal conductivity in complex oxides
P. Schelling - UCF PhysicsS. Phillpot - UF Materials Science and Engineering
In gas-turbines, the turbine blades are coated with an oxide to protect the metal blade from melting. The standard thermal barrier coating (TBC) material is yttria-stabilized zirconia (YSZ) due to its good strength and toughness and low thermal conductivity. However, there is significant interest in identifying new materials with even lower thermal conductivity. New materials with lower thermal conductivity will enable operation at higher temperatures and hence improved efficiency. Complex oxides are a potential new direction for improved TBC. Experiment and also simulation by Schelling and Phillpot have elucidated the mechanisms resulting in low thermal conductivity in YSZ and also fluorite-based pyrochlore materials for a wide range of compositions. We propose to elucidate heat transport in complex oxides based on the monoclinic zirconolite and hexagonal zirkelite structures. The prototype composition for zirkelite and zirconolite is CaZrTi2O7 and hence has a composition related to the pyrochlore A2B2O7. Other possible compositions exhibit these structures, including substitutions of Eu, Y, Th, Ce, Nb, and Mn. Using atomistic simulation, we will create property-composition maps that connect ion size and dynamical properties to the computed thermal conductivity. Computational study will performed using simple Buckingham potentials for the interactions, fit over a range of compositions. Density-functional theory (DFT) calculations will be used to provide data on lattice parameters and elastic constants where experimental data might be lacking. We will also elucidate the possibility of phase transitions and explore the issue of phase stability. The overall management of the project will involve Schelling at UCF providing any required first-principles results on structures and properties. The REU student will work with both groups to develop classical models and to perform the thermal conductivity calculations.
Studies of plagioclase mineral surfaces with applications to understanding the global carbon cycle
P. Schelling and S. Stolbov - UCF PhysicsThe weathering of silicates is an important sink for atmospheric carbon. As a result, the fidelity of climate change models depends on accurate models of silicate weathering. However, there are many open questions about the rate and mechanisms. Weathering primarily occurs by the dissolution of silicates which involves the release of ions, including Ca2+ and Mg2+, where they react with carbonic acid to form stable carbonates. The mechanism of dissolution, especially in the plagioclase feldspars, remains poorly understood. We willdevelop models of the plagioclase anorthite using density-functional theoryresults. The resulting model will be used to study the surface of anorthite, including the interaction with water molecules.
Other participating faculty
S. Sinnott - UF Materials Science and EngineeringHai-Ping Cheng - UF Physics
A. Masunov - UCF Chemistry