Condensed Matter Physics
The Condensed Matter Physics program at the University of Louisville focuses on cutting-edge research in nanoscience and photonics with its researchers engaged in theoretical (Wu), computational (Jayanthi, Liu, and Yu) and experimental studies (Sumanasekera) of nanomaterials and biomolecular films (Mendes).
Quantum mechanics based computer simulations and synthesis techniques are used to discover novel nanomaterials for efficient energy storage and energy production and for their potential use as components of nanoscale electronic devices and chemical sensors. The photonics group (Mendes) uses experimental tools based on integrated optics and surface waves to investigate the interface of biomolecular films.
Seminal contributions by the condensed matter theory (CMT) group include the developments of real-space electronic structure methods based on Green’s function techniques; algorithms for large-scale simulations; novel semi-empirical Hamiltonians (SCED-LCAO) for quantum-mechanics based simulations of complex materials, etc. The salient features of the SCED-LCAO method are: (i) it is developed in the framework of linear combination of atomic orbitals (LCAO), (ii) it includes electron-ion and electron-electron interactions that are modeled via phenomenological environment-dependent (ED) functions, and (iii) its framework allows a self-consistent (SC) calculation of the charge redistribution. The molecular dynamics scheme based on the SCED-LCAO Hamiltonian has been applied successfully to study a variety of problems that include: (i) the electromechanical responses in single-wall carbon nanotubes, (ii) the structure and stability of the entire family of carbon clusters (fullerenes, bucky-diamond structures, cage structures, etc.), (iii) structural and electronic properties of SiC nanostructures including nanowires, nanotubes, clusters, and graphitic-like sheets (CMT RESEARCH).
The research interests of the theory group also include modeling the growth mechanisms of thin films and nanostructures based on Kinetic Monte Carlo techniques and the rate equation theory (Liu) .
The research of the experimental condensed matter physics group led by Dr. Sumanasekera focuses around the following topics: synthesis and characterizations of novel nanostructures; electronic properties of hydrogenated and fluorinated graphene; efficient energy conversions of waste heat using high figure of merit thermoelectric materials; thermionics based on doped nano-diamonds; phonon confinements in semiconducting nanowires; chemical sensors based on carbon-based nanostructures and oxide nanowires; novel electrode materials for Li-ion batteries, and conducting transparent electrodes for solar applications (Sumanasekera).
The research activities of Dr. Mendes’ group focuses on novel analytical tools based on integrated optics and surface waves for research in biomolecular films and interface phenomena, the spectroscopic investigation of the physical/chemical properties of biomolecular films, and on the integration of nano-structured photonic devices with molecular assemblies for selective and sensitive transduction in chemical and biological materials. (Mendes).
- Chakram S. Jayanthi, Ph.D. (Indian Institute of Technology, Delhi)
- Shudun Liu, Ph.D. (Rutgers University)
- Sergio Mendes, Ph.D. (University of Arizona)
- Gamini Sumanasekera, Ph.D. (Indiana University)
- Shi-Yu Wu, Ph.D. (Cornell University)
- Ming Yu, Ph.D. (Hokkaido Institute of Technology,Japan)
- Coherent Treatments of the Self-Consistency and the Environment-Dependency in a Semi-Empirical Hamiltonian: Applications to Bulk Silicon, Silicon Surfaces, and Silicon Clusters, Phys. Rev. B 74, 155408 (2006).
- Geometric and Electronic Structures of Graphitic-like and Tubular Silicon Carbides: Ab-initioStudies, M. Yu, C.S. Jayanthi, and S.Y. Wu, ‘Phys. Rev. B82, 124027 (2010).
- Energetics, Relative Stabilities and Size-Dependent Properties of Nanosized Carbon Clusters of Different Families: Fullerenes, Bucky-Diamonds, Icosahedral, and Bulk-Truncated Structures, M. Yu, I. Chaudhuri, C. Leahy, S.Y. Wu, and C.S. Jayanthi, Journal of Chemical Physics 130, 184708 (2009).
- Stability and Mechanical Properties of Silicon Nanowires, Shudun Liu, C.S. Jayanthi, Zhenyu Zhang, and S.Y. Wu, Journal of Computational and Theoretical Nanoscience, Special Issue on Nanomorphology, Vol. 4, 275 (2007).
- Preferential growth of single-walled carbon nanotubes with metallic conductivity, Avetik R. Harutyunyan1 , Gugang Chen, Tereza M. Paronyan, Elena M. Pigos, Oleg A. Kuznetsov, Kapila Hewaparakrama, Seung Min Kim, Dmitri Zakharov, Eric A. Stach, and Gamini U. Sumanasekera, Science, 326 (5949), 116-120 (2009).
- Electrostatic deposition of graphene in a gaseous environment: a deterministic route for synthesizing rolled graphenes?, A. Sidorov D. Mudd, G. U. Sumanasekera, P. J. Ouseph, C. S. Jayanthi, Shi-Yu Wu, Nanotechnology, 20 (5), 55611 (2009).
- Large area synthesis of conical carbon nanotube arrays on graphite and tungsten foil substrates, S. Dumpala, J. B. Jasinski, G. U. Sumanasekera, M. K. Sunkara, CARBON, 49, 2725 (2011).
- Hypergolic fuel detection using individual single walled carbon nanotube networks, S. C. Desai, A. H. Willitsford, G. U. Sumanasekera, M. Yu, W. Q. Tian, C. S. Jayanthi, S. Y. Wu, JOURNAL OF APPLIED PHYSICS, 107 (11), 114509 (2010).
- Low-Loss Optical Waveguides for the Near Ultra-Violet and Visible Spectral Regions with Al2O3 Thin Films from Atomic Layer Deposition, Mustafa M. Aslan, Nathan A. Webster, Courtney L. Byard, Marcelo B. Pereira, Colin M. Hayes, Rodrigo S. Wiederkehr, and Sergio B. Mendes, Thin Solid Films (2010), 518, 4935-4940.
- Solid Immersion Lens at the Aplanatic Condition for Enhancing the Spectral Bandwidth of a Waveguide Grating Coupler, Marcelo B. Pereira, Jill S. Craven, and Sergio B. Mendes, Optical Eng (2010), 49, 124601.
- Broadband Spectroelectrochemical Interrogation of Molecular Thin Films by Single-Mode Electro-Active Integrated Optical Waveguides, Sergio B. Mendes, S. Scott. Saavedra, and Neal R. Armstrong, invited book chapter in "Optical Guided-Wave Chemical and Biosensors," Editors: Zourob, M. and Lakhtakia, A.; Springer-Verlag book series on Chemical Sensors and Biosensors (2010), ISBN 978-3-540-88241-1, 101-129.
- Investigations of the Q and CT Bands of Cytochrome c Adsorbed onto Alumina Surfaces Using Broadband Spectroscopy with Single-Mode Integrated Optical Waveguides, Rodrigo S. Wiederkehr, Geoffrey C. Hoops, Mustafa M. Aslan, Courtney L. Byard andSergio B. Mendes, J. Phys. Chem. C (2009), 113, 8306-8312.
- An Electroactive Fiber Optic Chip for Spectroelectrochemical Characterization of Ultra-Thin Redox Active Films, Brooke M. Beam, Neal R, Armstrong, and Sergio B. Mendes, Analyst (2009) 134, 454-459.