Yijia Gu, a Ph.D. student working in...
Assistant Professor of Materials Science and Engineering
N-241 Millennium Science Complex
Dr. Ismaila Dabo received his B.S. and M.S. in Mechanical Engineering from Ecole Polytechnique (France) in 2002 and 2004, and graduated with a Ph.D. in Materials Science and Engineering from the Massachusetts Institute of Technology (MIT) in 2008. His doctoral research under the supervision of Nicola Marzari was dedicated to predicting the electrical response of quantum systems embedded in electrochemical environments and to studying chemical poisoning in low-temperature fuel cells. After graduation, Ismaila Dabo became a postdoctoral researcher and then a permanent researcher at Ecole des Ponts ParisTech, University of Paris-Est (France). He joined the Department of Materials Science and Engineering at Penn State in 2013. His research and teaching interests are in the broad areas of materials modeling, electrochemistry, photochemistry, electronic-structure theories, continuum solvation theories, and the development and implementation of advanced materials simulation methods.
Dr. Dabo's group develops and uses quantum and multiscale computational methods to understand the performance of materials for energy conversion and storage.
Our primary focus is on studying electrochemical and photochemical cells (fuel cells, electrical batteries, electrochemical capacitors, solar fuel generators), which have become of utmost importance to global energy sustainability. Electrochemical and photochemical cells are among the most promising technology options to overcome the intermittency of wind and solar energies, and improve energy efficiency.
Our main expertise is in understanding chemical reactions and light-induced excitations at electrochemical and photochemical interfaces. This understanding requires the comprehensive description of the charge-transfer mechanisms that underlie most electrochemical and photochemical processes. To this end, we develop accurate and efficient quantum methods that overcome the main limitations of conventional effective-field approximations in describing charge-transfer phenomena, and we implement reliable multiscale methods to capture the critical influence of the electrode and electrolyte environments.
Our ultimate goal is to use the predictive power of these advanced computational methods to break down the complexity of materials problems and accelerate materials discovery in electrochemistry and photochemistry.
The group offers stimulating opportunities to work at the interface between materials science, physics, chemistry, and computer science on both fundamental and applied research in close connection with experiment.
The Nobel Prize in Chemistry 2013 awarded to Martin Karplus, Michael Levitt, Arieh Warshel for the development of multiscale models that combine quantum, classical, and continuum theories to describe complex chemical processes.
List of selected publications:
Himmetoglu B., Marchenko A., Dabo I., Cococcioni M., “Role of electronic localization in the phosphorescence of iridium sensitizing dyes”, Journal of Chemical Physics 137, 154309 (2012), DOI: 10.1063/1.4757286
Dabo I., “Resilience of gas-phase anharmonicity in the vibrational response of adsorbed carbon monoxide and breakdown under electrical conditions”, Physical Review B 86, 035139 (2012), DOI: 10.1103/PhysRevB.86.035139
Andreussi O., Dabo I., Marzari N., “Revised self-consistent continuum solvation in electronic-structure calculations”, Journal of Chemical Physics 136, 064102 (2012), DOI: 10.1063/1.3676407
Dabo I., Ferretti A., Poilvert N., Li Y. L., Marzari N., Cococcioni M., “Koopmans’ condition for density-functional theory”, Physical Review B 82, 115121 (2010), DOI: 10.1103/PhysRevB.82.115121
Dabo I., Bonnet N., Li Y. L., Marzari N., “Ab-initio electrochemical properties of electrode surfaces”, Fuel cell science : theory, fundamentals, and biocatalysis edited by A. Wieckowski and J. Nørskov, Wiley (2010), ISBN: 978-0-470-41029-5
Giannozzi P., Baroni, S., Bonini N., Calandra M., Car R., Cavazzoni C., Ceresoli D., Chiarotti G. L., Cococcioni M., Dabo I., Dal Corso A., Fabris S., Fratesi G., de Gironcoli S., Gebauer R., Gerstmann U., Gougoussis C., Kokalj A., Lazzeri M., Martin-Samos L., Marzari N., Mauri F., Mazzarello R., Paolini S., Pasquarello A., Paulatto L., Sbraccia C., Scandolo S., Sclauzero G., Seitsonen A. P., Smogunov A., Umari, P., Wentzcovitch, R. M., “Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials”, Journal of Physics: Condensed Matter 21, 395502 (2009), DOI: 10.1088/0953-8984/21/39/395502
Dabo I., Kozinsky B., Singh-Miller N. E., Marzari N., “Electrostatics in periodic boundary conditions and real-space corrections”, Physical Review B 77, 115139 (2008), DOI: 10.1103/PhysRevB.77.115139
Dabo I., Wieckowski A., Marzari N., “Vibrational recognition of adsorption sites for CO on platinum and platinum-ruthenium surfaces”, Journal of the American Chemical Society 129, 11045-11052 (2007), DOI: 10.1021/ja067944u
A team of Penn State researchers has developed field effect transistors using graphene and hexagonal boron nitride on a 75-millimeter wafer, a significant step toward graphene-based electronics.
Assistant Professor of Materials Science and Engineering
N-232 Millennium Science Complex
Roman Engel-Herbert received a Diploma in Physics from the Friedrich-Schiller University Jena, Germany. He later joined the Paul-Drude-Institute for Solid State Electronics for his graduate studies under the direction of Klaus H. Ploog and Thorsten Hesjedal and received a Ph.D. degree in Experimental Physics from the Humboldt University Berlin. He then followed an invitation to the University of Waterloo in Canada before he accepted a postdoc position in the Materials Department at the University of California Santa Barbara. Dr. Engel-Herbert joined the faculty of Materials Science and Engineering at Penn State University in 2010. His current research interests are the growth of binary and complex oxides using thin film deposition techniques and their integration with conventional semiconductors as well as the analysis of magnetic domain structures.
Research efforts are focused on the growth and characterization of oxide thin films. This class of materials has an unparalleled spectrum of physical properties which makes them very interesting for a variety of applications ranging from energy generation, sensors and actuators to memory and logic device concepts. The monolithic integration of oxide thin films to cross-couple different functionalities, novel interface phenomena, epitaxial stabilization of unfavorable phases and strain engineering provide additional degrees of freedom that are largely unexplored, which further extend the opportunities to tailor material properties. Although oxide films can be grown with high structural perfection, intrinsic material properties might be obscured by a high level of unintentional defects.
Molecular beam epitaxy (MBE) is the main synthesis method employed by this group. The system design facilitates the deposition of metal organic molecules and thus combines low energetic deposition techniques in a unique way, dubbed "Hybrid MBE". Stoichiometric control and suppression of defect formation during growth as well as doping strategies are addressed. Structural characterization methods encompass X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). Hall measurements and admittance spectroscopy are used for electrical characterization.
Another research area are magnetic domain structures in confined geometries with nanoscale dimensions. Domain arrangements, their formation and stability in the presence of an external magnetic field are studied by magnetic force microscopy. Current induced magnetization dynamics, such as spin transfer torque magnetization reversal and domain wall motion, are investigated using micromagnetic simulation. Magnetic nanostructures are building blocks of spin-electronic devices and the study of these phenomena is imperative for their successful application in the area of information technology.
Suzanne Mohney has been a Professor of Materials Science and Engineering since 2004 and holds the title of Professor of Electrical Engineering. Prior to 2004, she was an Associate or Assistant Professor at Penn State. She earned a Ph.D. in Materials Science at the University of Wisconsin in 1994 and a B.S.Ch.E. summa cum laude from Washington University in St. Louis in 1987. She has been a recipient of research awards from The Electrochemical Society and the Penn State College of Earth and Mineral Science, as well as an award for outstanding teaching from the College. She currently serves as the Editor-in-Chief of the TMS-IEEE Journal of Electronic Materials.
Our research group investigates electronic and photonic materials. Many of our projects focus on metal/semiconductor contacts for electronic and optoelectronic devices. We are also investigating semiconductor nanowires for nanoscale electronics and quantum dots for more efficient white lighting. In addition, we study metallic thin films for interconnects, electronic packaging, and microelectromechanical systems (MEMS).
The metal/semiconductor contacts we study are an essential part of electronic and optoelectronic devices, including transistors, laser diodes, and solar cells. Controlled metallurgical reactions between the contact metals and the semiconductor are required to engineer the electrical properties of the contacts. On the other hand, uncontrolled reactions can result in nonuniform contacts and poor thermal stability during processing, packaging, or long-term operation. Through an examination of the thermodynamics and kinetics governing interfacial reactions, contacts with greatly improved thermal stability, uniformity, and electrical performance can be designed. This work also involves study of current transport in the contacts and materials characterization using techniques such as transmission electron microscopy, Auger depth profiling, and atomic force microscopy. We work with many families of semiconductors, some of which have been commercialized and others that are in the early stages of development. These materials include III-V compound semiconductors, GaN, SiC, and Si.
Our research on semiconductor nanowires and quantum dots, MEMS, and novel semiconductors is very interdisciplinary, involving collaborations with faculty in electrical engineering, physics, chemical engineering, and other materials disciplines. We also frequently work with researchers from government laboratories and industry.
Long-Qing Chen is Distinguished Professor of Materials Science and Engineering and Professor of Engineering Science and Mechanics at the Pennsylvania State University. He is a short-term visiting Professor of Materials Science and Engineering at Tsinghua University under the short-term 1000-Scholar program, a guest Professor of Materials Science and Engineering at Zhejiang University, and a guest Professor of Physics at the Beijing University of Science and Technology in China. He received his B.S. degree in Materials Science and Engineering from Zhejiang University in China in 1982. After spending one year as an assistant instructor at Zhejiang University, he came to the United States in 1983 and received his M.S. degree in Materials Science and Engineering from the State University of New York at Stony Brook in 1985 and a Ph.D. degree in Materials Science and Engineering from the Massachusetts Institute of Technology (MIT) in 1990. After a two-year post-doc appointment with Professor Armen G. Khachaturyanat Rutgers University, he joined the faculty at Penn State as an Assistant Professor of Materials Science and Engineering in 1992. He was promoted to Associated Professor in 1998 and Professor in 2002. Professor Chen teaches undergraduate thermodynamics of materials and graduate kinetics of materials processes and also co-teaches one graduate course and one undergraduate course in computational materials science in the department. Professor Chen's main research interest is developing multiscale computational models for predicting microstructure evolution in materials using a combination of atomistic/first-principles calculations and phase-field methods. In particular, he is interested in microstructure evolution during phase transformations, grain growth, Ostwald ripening, ferroelectric and multiferroic domain switching, and coupled ionic/electronic transport in electrochemical systems. His research group collaborates actively with numerous experimental groups, applied mathematicians, and other fellow computational materials scientists and physicists as well as with more than a dozen companies and national labs. Professor Chen has published over 350 authored or co-authored papers (H-index = 51, Number of Citations >10,000), 1 patent licensed by Intel, and co-edited 3 books in the area of computational materials science of microstructures and properties. He has given more than 200 invited talks including 6 at the Gordon Research Conferences. Professor Chen's current and former graduate students have received more than 40 awards including Materials Research Society Graduate Student Gold and Silver Medal Awards, American Ceramic Society Graduate Excellence in Materials Science Awards, Acta Materialia best student paper award, Penn State Materials Research Institute best Ph.D. thesis research award, TMS Young Leader Award, etc. Professor Chen received numerous awards for his work including:
Dr. Chen’s main research interest is in the fundamental understanding of the thermodynamics and kinetics of phase transformations and mesoscale microstructure evolution in bulk solid and thin films using computer simulations. Essentially all engineering materials contain certain types of microstructures, and our success of designing new materials is largely dependent on our ability to control them. Microstructure is a general term that refers to a spatial distribution of structural features that can be phases of different compositions and/or crystal structures, or grains of different orientations, or domains of different structural variants, or domains of different electrical or magnetic polarization, as well as structural defects such as dislocations. It is the size, shape, and spatial arrangement of the local structural features that determine the physical properties of a material such as mechanical, electrical, magnetic and optical properties. For the last decade, Dr. Chen’s group at Penn State is particularly active in developing phase-field models for microstructure evolution during various materials processes including grain growth, coherent precipitation, ferroelectric domain formation, particle coarsening, domain structure evolution in thin films, phase transformation in the presence of structural defects, and effect of stress on microstructure evolution. Current research focus is on the effect of stress/strain on ferroelectric phase transitions and domain structure evolution in ferroelectric and multiferroic thin films, domain structures in ferromagnetic shape memory alloys, electrode microstructure evolution in solid oxide fuel cells and batteries, precipitate microstructure evolution in Al-, Mg-, Ti- and Ni-alloys, strain-dominated morphological evolution, effect of defects such as dislocations on microstructure evolution. Dr. Chen’s group collaborates extensively with experimentalists and with industry.
Alloy development for aerospace and automobile iapplications
Ferroelectric and ferromagnetic thin films for memory, capacitor and electromechanical system applications
Solid oxide fuel cells and batteries
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