Research activities
 
My research activities are centered within the area of computational physics with an emphasis on materials science and, in particular,  the application of quantum theory to real materials.  Much of my work is focused on understanding the behavior of matter at small length scales, or within the nano-regime.  At such length scales, the properties of matter often deviate from the macroscopic or bulk limit owing to quantum confinement – the physical confinement of electronic interactions.  
 
My research group employs two physical ingredients in our attempt to understand nano-structures:  (1)  pseudopotentials, which allows one to focus solely on the valence states, and (2)  density functional theory, which allows one to map the all electron problem to a one electron problem.   Our work is multidiscipline, involving computer scientists and physical scientists.  My work with computer scientists develops new high performance algorithms targeted at solving the electronic structure problem via a solution of the Kohn-Sham equation.   My work with physical scientists applies these algorithms  to complex systems of interest such as atomic clusters, quantum dots, nanowires, and liquids.
 
Examples of my recent work can be found in the following papers:
 
  1.  T.-L. Chan, M. L. Tiago, E. Kaxiras and J.R. Chelikowsky, “Size Limits on Doping Phosphorus into Silicon Nanocrystals,”  Nano Letters 8, 596 (2008)
  2. L. Kong, J.R. Chelikowsky, J.B. Neaton, and S.G. Louie:  “Real-space pseudopotential calculations of spin-dependent electron transport in quantum point contacts,” Phys. Rev. B 76, 235422 (2007).
  3. G. Rollmann, M.E. Gruner, A. Hucht, P. Entel, M.L. Tiago and J.R. Chelikowsky: “Shell-wise Mackay transformation in iron nano-clusters,'' Phys. Rev. Lett. 99, 083402 (2007).
  4. M.M.G. Alemany, X. Huang, M.L. Tiago, and J.R. Chelikowsky:  “p-type Doping in Indium Phosphide Nanowires: the Role of Dimensionality and Quantum Confinement in the Acceptor Impurity States,” Nano Lett.  7, 1878 (2007).
  5. G. Dalpian and J.R. Chelikowsky: “Self-Purification on Semiconductor Nanocrystals,” Physical Review Letters 96, 226802 (2006).
  6. M.L. Tiago, Y. Zhou, M.M.G. Alemany, Y. Saad and J.R. Chelikowsky: “Evolution of Magnetism in Iron from the Atom to the Bulk,”  Physical Review Letters 97, 147201 (2006).
  7. G. Dalpian, M.L. Tiago, M. Lopez del Puerto and J.R. Chelikowsky:  “Symmetry considerations for semiconductor nanocrystals,”  Nanoletters 6, 501 (2006).  
  8. M. Lopez del Puerto, M.L. Tiago, and J.R. Chelikowsky:  “Excitonic effects and optical properties of passivated CdSe clusters,”  Phys. Rev. Lett. 97, 096401 (2006).
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Also check out my full list of publications here.
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