Browsing by Autor "A. Camacho"

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    Efficient control of coulomb enhanced second harmonic generation from excitonic transitions in quantum dot ensembles
    (Royal Society of Chemistry, 2015) Hanz Y. Ramírez; Jefferson Flórez; A. Camacho
    In this work, the second harmonic generation from excitonic transitions in semiconductor quantum dots is computationally studied. By integrating a density matrix treatment with a partial configuration interaction approach, we obtain the second order susceptibility as a function of externally applied electric and magnetic fields for highly confined neutral and charged excitons. Our results show an enhancement in the nonlinear response with respect to analogous optical processes based on intraband transitions, and predict their efficient tunability by taking advantage of the interplay between Coulomb effects and field-driven wave function manipulation.
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    Electronic Structure of (001) Semiconducting MTe Surfaces (M = Zn, Cd, Hg)
    (Wiley, 1990) F. J. Rodríguez; A. Camacho; Luis Quiroga; R. Baquero
    Abstract By using the tight‐binding scheme with ten orbitals per atom (SP 3 S* and two spin orientations) the electronic projected bulk band structure, surface band structure (both anion‐and cation‐terminated surfaces), and the wave‐vector‐resolved density of states for these II‐VI semiconductors are calculated. A quickly convergent iterative technique is employed for calculating the Green function of the actual semi‐infinite crystal. This calculational method allows to precise very accurately, the energy of localized surface states. All the materials considered in this work present surface states with energies lying in the fundamental gap as well as surface states in the lenses opened in the projected bulk valence‐band continum. The atomic weight of each surface state is determined. The states in the fundamental gap turn out to be ‘bridge‐bond’‐type states for anion‐terminated surfaces and ‘dangling‐bond’‐type states for cation‐terminated surfaces.