Browsing by Author "59ffa29f-d96f-4bc5-b840-3a46d060352e"

Now showing items 1-17 of 17

    • openAccess   Anisotropy of spin–orbit induced electron spin relaxation in [001] and [111] grown GaAs quantum dots 

      Segarra, Carlos; Planelles, Josep; Climente, Juan I.; Rajadell Viciano, Fernando IOP Publishing (2015)
      We report a systematic study of the spin relaxation anisotropy between single electron Zeeman sublevels in three-dimensional cuboidal GaAs quantum dots (QDs). The QDs are subject to an in-plane magnetic field. As the field ...

    • openAccess   Band structure engineering via piezoelectric fields in strained anisotropic CdSe/CdS nanocrystals 

      Christodoulou, Sotirios; Rajadell Viciano, Fernando; Casu, Alberto; Vaccaro, Gianfranco; Grim, Joel Q.; Genovese, Alessandro; Manna, Liberato; Climente, Juan I.; Meinardi, Francesco; Rainò, Gabriele; Stöferle, Thilo; Mahrt, Rainer F.; Planelles, Josep; Brovelli, Sergio; Moreels, Iwan Nature Publishing Group (2015)
      Strain in colloidal heteronanocrystals with non-centrosymmetric lattices presents a unique opportunity for controlling optoelectronic properties and adds a new degree of freedom to existing wavefunction engineering and ...

    • openAccess   Delocalized image surface states in defects free SiO2 hollow nanospheres 

      Movilla, Jose L.; Rajadell Viciano, Fernando; Planelles, Josep American Institute of Physics (2008)
      Delocalized image surface states in free-standing hollow silica nanospheres populated with one or two electrons or an exciton are theoretically predicted for a wide range of internal radii and shell thicknesses. The ...

    • openAccess   Dielectric control of spin in semiconductor spherical quantum dots 

      Royo Valls, Miguel; Rajadell Viciano, Fernando; Planelles, Josep American Institute of Physics (2008)
      The ground state electronic configuration of semiconductor spherical quantum dots populated with different numbers of excess electrons, for different radii and dielectric constants of the embedding medium is calculated ...

    • openAccess   Effect of strain and variable mass on the formation of antibonding hole ground states in InAs quantum dot molecules 

      Planelles, Josep; Climente, Juan I.; Rajadell Viciano, Fernando; Doty, Matthew F.; Bracker, Allan S.; Gammon, Daniel American Physical Society (2010-10-04)
      Using four-band k·p Hamiltonians, we study how biaxial strain and position-dependent effective masses influence hole tunneling in vertically coupled InAs/GaAs quantum dots. Strain reduces the tunneling and hence the critical ...

    • openAccess   Electronic Origin of Linearly Polarized Emission in CdSe/CdS Dot-in-Rod Heterostructures 

      Planelles, Josep; Rajadell Viciano, Fernando; Climente, Juan I. American Chemical Society (2016-11)
      Seeded CdSe/CdS nanorods exhibit intense polarized emission along the rod main axis. The degree of linear polarization cannot be explained by dielectric effects alone; an additional electronic contribution is present whose ...

    • openAccess   Electrons, holes, and excitons in GaAs polytype quantum dots 

      Climente, Juan I.; Segarra, Carlos; Rajadell Viciano, Fernando; Planelles, Josep American Institute of Physics (2016)
      Single and multi-band k⋅p Hamiltonians for GaAs crystal phase quantum dots are used to assess ongoing experimental activity on the role of such factors as quantum confinement, spontaneous polarization,valence band mixing, ...

    • openAccess   Excitons in core-only, core-shell and core-crown CdSe nanoplatelets: Interplay between in-plane electron-hole correlation, spatial confinement, and dielectric confinement 

      Rajadell Viciano, Fernando; Climente, Juan I.; Planelles, Josep American Physical Society (2017)
      Using semianalytical models we calculate the energy, effective Bohr radius, and radiative lifetime of neutral excitons confined in CdSe colloidal nanoplatelets (NPLs). The excitonic properties are largely governed by ...

    • closedAccess   Excitons, Biexcitons, and Trions in CdSe Nanorods 

      Rajadell Viciano, Fernando; Climente, Juan I.; Planelles, Josep; Bertoni, Andrea American Chemical Society (2009)
      We calculate the recombination energies and probabilities of neutral excitons (X), singly charged excitons (X±), and biexcitons (XX) in CdSe quantum dots of variable length. For spherical dots the relative position of the ...

    • closedAccess   Hole Band Mixing in CdS and CdSe Quantum Dots and Quantum Rods 

      Planelles, Josep; Rajadell Viciano, Fernando; Climente, Juan I. American Chemical Society (2010)
      Using a six-band k·p Hamiltonian for wurtzite lattice, we study the hole ground state symmetry and composition in spherical quantum dots and elongated quantum rods made of CdS and CdSe. The ground state crossovers which ...

    • openAccess   Hole spin relaxation in InAS/GaAs quantum dot molecules 

      Segarra, Carlos; Climente, Juan I.; Rajadell Viciano, Fernando; Planelles, Josep IOP Publishing Ltd (2015-09)
      We calculate the spin–orbit induced hole spin relaxation between Zeeman sublevels of vertically stacked InAs quantum dots. The widely used Luttinger–Kohn Hamiltonian, which considers coupling of heavy- and light-holes, ...

    • openAccess   Influence of Polytypism on the Electronic Structure of CdSe/CdS and CdSe/CdSe Core/Shell Nanocrystals 

      Segarra, Carlos; Rajadell Viciano, Fernando; Climente, Juan I.; Planelles, Josep American Chemical Society (2017-03)
      We address theoretically differences and similarities on the electronic structure of CdSe/CdS dot-in-dot nanocrystals (NCs) with wurtzite/wurtzite (WZ/WZ), zinc-blende/zinc-blende (ZB/ZB) and polytype ZB/WZ crystalline ...

    • openAccess   Large hole spin anticrossings in InAs/GaAs double quantum dots 

      Rajadell Viciano, Fernando; Planelles, Josep; Climente, Juan I. AIP Publishing (2013-09-23)
      We show that hole states in InAs/GaAs double quantum dots can exhibit spin anticrossings of up to 1 meV, according to simulations with a three dimensional Burt-Foreman Hamiltonian including strain and piezoelectric fields. ...

    • openAccess   Piezoelectric Control of the Exciton Wave Function in Colloidal CdSe/CdS Nanocrystals 

      Segarra, Carlos; Climente, Juan I.; Polovitsyn, Anatolii; Rajadell Viciano, Fernando; Moreels, Iwan; Planelles, Josep American Chemical Society (2016-05-25)
      Using multiband k·p calculations, we show that strain-engineered piezoelectricity is a powerful tool to modulate the electron−hole spatial separation in a wide class of wurtzite CdSe/CdS nanocrystals. The inherent ...

    • openAccess   Strain in free standing CdSe/CdS core-shell nanorods 

      Rajadell Viciano, Fernando; Planelles, Josep; Royo Valls, Miguel American Institute of Physics (AIP) (2012)
      The main characteristic strain trends in free-standing II–VI wurtzite semiconductor nanorods coated with a few-monolayers shell are reported. Calculations for different aspect ratios and shell thicknesses show that these ...

    • openAccess   Symmetry-induced hole-spin mixing in quantum dot molecules 

      Planelles, Josep; Rajadell Viciano, Fernando; Climente, Juan I. American Physical Society (2015)
      We investigate theoretically the spin purity of single holes confined in vertically coupled GaAs/AlGaAs quantum dots (QDs) under longitudinal magnetic fields. A unique behavior is observed for triangular QDs, by which ...

    • openAccess   Temperature dependence of the spectral band shape of CdSe nanodots and nanorods 

      Climente, Juan I.; Planelles, Josep; Rajadell Viciano, Fernando American Physical Society (2009)
      We study theoretically the effect of thermal population on the emission spectrum of single CdSe nanocrystals. Quantum confinement leads to nonsimple emission band shapes, which have different characteristics for excitons, ...