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Computational Biophysics We investigate energetics, structures, thermodynamics, and kinetics of biomolecules via computational tools. Of particular interest are first-principles calculations of biomolecular interactions, structure prediction of multiprotein complexes, thermodynamics, and kinetic properties of protein-protein association. We build computational tools to simulate biomolecular interactions.
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Computational Methods The Center supports the Office of Naval Research's Grand Challenge "Navy Materials by Design" by developing and maintaining a variety of computational tools. These include first-principles methods based on density-functional theory, specialized models for highly correlated systems, efficient tight-binding and overlapping-atom models, and simulation methods spanning multiple length scales.
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Energy Storage We investigate the underlying physical and chemical principles that facilitate efficient energy storage and creation. Through computationally driven insight into the relationships between structure, composition, and performance, we evaluate materials for their usefulness as battery cathodes and anodes or as fuel cell catalysts.
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Magnetic Materials and Magnetism in Semiconductors The Center studies a broad range of magnetic materials, from hard magnetic materials to dilute magnetic semiconductors. Some of these materials form the basis of current magnetoelectronic technologies, while others—both soft and hard magnets—are being studied for future applications. In addition, this research focuses on semiconductors that are rendered magnetic by either intrinsic or extrinsic effects. These materials, which offer the advantages of semiconductors combined with the non-volatile properties of magnetic materials, are the materials foundation for future "spintronics" technologies.
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Mechanical Properties We apply computational methods including first principles, tight binding, interatomic potentials, and coupling of length scales approaches to the simulation of mechanical properties. Applications range from static calculations of quantities such as ideal strength and ductility criteria, to dynamic simulations of finite-temperature ideal strength and dynamic fracture.
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Quantum Dots Quantum dots are a new form of matter that can be considered as "artificial atoms." They have linear discrete absorption spectra (like atoms) and photoluminescence that is tunable (by changing the dot size) over a wide range, from far infrared to deep ultraviolet. They can be moved around for different purposes:
- to form quantum-dot "molecules"
- to form three-dimensional "meta-crystals" that form new materials having tailored lattice constants, tailored crystal symmetry and tailored band structure
- to act as dopants in other materials
- to be joined with a larger molecule to form a super molecule.
In this way, instead of 109 elements we have at our disposal, in principle, an unlimited number of atomic "elements."
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Quantum Information A broad program is underway to use single-electron quantum dots in silicon for quantum information processing. A theoretical description of this system is necessarily multiscale, ranging from density functional theory at the atomic level to time-dependent model Hamiltonian calculations of many-dot systems. Optimal experimental designs to minimize decoherence will be examined.
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Radiation in Matter Quantum-open-systems (reduced-density-matrix) approaches are developed for non-equilibrium (possibly coherent) electromagnetic interactions in quantized electronic systems, in the presence of environmental relaxation and decoherence phenomena. The electronic systems of interest include ensembles of many-electron atoms, energetic electron beams in crystals and in electric and magnetic fields, and semiconductor materials (ideal crystals and heterostructures). Linear and non-linear optical phenomena are investigated within the frameworks of semi-classical and fully-quantum mechanical (QED) formulations.
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Superconductors Superconducting materials are used in a wide variety of defense and civilian technologies. Navy applications include superconducting motors for electric drives, microwave devices, superconducting magnets, and mine sweeping.
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Surfaces and Interfaces We investigate the physics of clean and adsorbed surfaces of semiconductors and metals. Reduced dimensionality plays an important role at surfaces, profoundly influencing electronic and magnetic properties. We also study the interfaces between materials, which are at the heart of technologically important phenomena such as grain-boundary formation, band-offset engineering, and spin injection.
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