Browsing Dr. Achintya Singha by Title

Now showing items 1-6 of 6

    • Correlated electrons in optically tunable quantum dots: Building an electron dimer molecule 

      Singha, Achintya; Pellegrini, Vittorio; Pinczuk, Aron; Pfeiffer, Loren N.; West, Ken W.; Rontani, Massimo (American Physical Society, 2010-06-15)
      We observe the low-lying excitations of a molecular dimer formed by two electrons in a GaAs semiconductor quantum dot in which the number of confined electrons is tuned by optical illumination. By employing inelastic light ...

    • Delocalized-localized transition in a semiconductor two-dimensional honeycomb lattice 

      De Simoni, G.; Singha, Achintya; Gibertini, M.; Karmakar, B.; Polini, M.; Piazza, V.; Pfeiffer, L. N.; West, K. W.; Beltram, F.; Pellegrini, V. (AMER INST PHYSICS, 2010-09-27)
      We report the magnetotransport properties of a two-dimensional electron gas in a modulation-doped AlGaAs/GaAs heterostructure subjected to a lateral potential with honeycomb geometry. Periodic oscillations of the ...

    • Engineering artificial graphene in a two-dimensional electron gas 

      Gibertini, M.; Singha, Achintya; Pellegrini, Vittorio; Polini, Marco; Vignale, Giovanni; Pinczuk, Aron; Pfeiffer, Loren N.; West, Ken W. (AMER PHYSICAL SOC, 2009-06-01)
      At low energy, electrons in doped graphene sheets behave like massless Dirac fermions with a Fermi velocity, which does not depend on carrier density. Here we show that modulating a two-dimensional electron gas with a ...

    • Optical anisotropy of electronic excitations in elliptical quantum dots 

      Singha, Achintya; Pellegrini, Vittorio; Kalliakos, Sokratis; Karmakar, Biswajit; Pinczuk, Aron; Pfeiffer, Loren N.; West, Ken W. (AMER INST PHYSICS, CIRCULATION & FULFILLMENT DIV, 2009-02-16)
      The authors report that anisotropic confining potentials in laterally coupled semiconductor quantum dots (QDs) have large impacts in optical transitions and energies of intershell collective electronic excitations. The ...

    • Probing collective modes of correlated states of few electrons in semiconductor quantum dots 

      Kalliakos, S.; Rontani, M.; Pellegrini, V.; Pinczuk, A.; Singha, Achintya; Garcia, C. P.; Goldoni, G.; Molinari, E.; Pfeiffer, L. N.; West, K. W. (PERGAMON-ELSEVIER SCIENCE LTD, 2009-09-01)
      Low-lying collective excitations above highly correlated ground states of few interacting electrons confined in GaAs semiconductor quantum dots are probed by resonant inelastic light scattering. We highlight that separate ...

    • Two-Dimensional Mott-Hubbard Electrons in an Artificial Honeycomb Lattice 

      Singha, Achintya; Gibertini, M.; Karmakar, B.; Yuan, S.; Polini, M.; Vignale, Giovanni; Katsnelson, M. I.; Pinczuk, A.; Pfeiffer, L. N.; West, K. W.; Pellegrini, V. (AMER ASSOC ADVANCEMENT SCIENCE, 2011-06-03)
      Artificial crystal lattices can be used to tune repulsive Coulomb interactions between electrons. We trapped electrons, confined as a two-dimensional gas in a gallium arsenide quantum well, in a nanofabricated lattice with ...