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We present a theoretical study of Ge-core/Si-shell nanocrystals in a wide bandgap matrix and compare the results with experimental data obtained from the samples prepared by co-sputtering. The empirical tight-binding technique allows us to…

Mesoscale and Nanoscale Physics · Physics 2017-03-07 M. O. Nestoklon , A. N. Poddubny , P. Voisin , K. Dohnalova

Recent photoabsorption measurements have revealed a rich fine structure in the collective charge-density excitation spectrum of few-electron quantum dots in the presence of magnetic fields. We have performed systematic computational studies…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 C. A. Ullrich , G. Vignale

Electrostatic confinement in semiconductors provides a flexible platform for the emulation of interacting electrons in a two-dimensional lattice, including in the presence of gauge fields. This combination offers the potential to realize a…

Mesoscale and Nanoscale Physics · Physics 2019-06-04 T. Hensgens , U. Mukhopadhyay , P. Barthelemy , S. Fallahi , G. C. Gardner , C. Reichl , W. Wegscheider , M. J. Manfra , L. M. K. Vandersypen

he properties of excitons formed in spherical quantum dots are studied using the $\mathbf{k}\cdot\mathbf{p}$ method within the Hartree approximation. The spherical quantum dots considered have a central core and several concentric layers of…

Mesoscale and Nanoscale Physics · Physics 2019-10-11 Mariano Garagiola , Omar Osenda

A multiscale QM/classical approach is presented, that is able to model the optical properties of complex nanostructures composed of a molecular system adsorbed on metal nanoparticles. The latter are described by a combined…

Chemical Physics · Physics 2024-10-29 Pablo Grobas Illobre , Piero Lafiosca , Luca Bonatti , Tommaso Giovannini , Chiara Cappelli

We present a symmetry-based calculation of the electronic structure of a compound semiconductor quantum dot (QD) in the sp^3s* tight-binding model including the spin-orbit interaction. The Hamiltonian matrix is diagonalized exactly for CdTe…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 J. Perez-Conde , A. K. Bhattacharjee

In this paper, we study theoretically the electron and spectral properties of Ge1-xSnx systems, including alloys, cubic- and spherical quantum dots. The single-particle electron and hole states are calculated within the sp3d5s*…

Mesoscale and Nanoscale Physics · Physics 2024-06-21 Krzysztof Gawarecki , Jakub Ziembicki , Paweł Scharoch , Robert Kudrawiec

Special optical structures composed of superconducting nanostructure based on the elemental type-II and layered high-Tc superconductors are proposed. The photonic band structure and the optical S-matrix are calculated for these proposed…

We suggest to exploit dielectric-metal core-shell nanostructures for efficient resonant and yet broadband absorption of infrared radiation with deeply subwavelength configurations. Realizing that nanostructures would efficiently absorb…

Single layer core/shell structures consisting of graphene as core and hexagonal boron nitride as shell are studied using first-principles plane wave method within density functional theory. Electronic energy level structure is analysed as a…

Mesoscale and Nanoscale Physics · Physics 2014-08-05 S. Cahangirov , S. Ciraci

We experimentally and theoretically investigate the non-degenerate two-photon absorption coefficient $\beta(\omega_1,\omega_2)$ in the prototypical semiconductor ZnSe. In particular, we provide a comprehensive data set on the dependence of…

Mesoscale and Nanoscale Physics · Physics 2021-08-13 L. Krauss-Kodytek , W. -R. Hannes , T. Meier , C. Ruppert , M. Betz

Wide bandgap semiconductor heterostructures based on nanowires have attracted great interest as one of the nanoscale building blocks for the development of novel optoelectronic devices. Owing to the critical role of heterogeneities and…

The structural properties of the $Zn_xMg_{1-xS_ySe_{1-y}}$ solid solutions are determined by a combination of the computational alchemy and the cluster expansion methods with Monte Carlo simulations. We determine the phase diagram of the…

Materials Science · Physics 2009-10-30 Antonino Marco Saitta , Stefano de Gironcoli , Stefano Baroni

The electronic properties of quasi-one-dimensional anatase TiO2 nanostructures, in the form of thin nanowires having (101) and (001) facets, have been systematically investigated using the standard, hybrid density functional and…

Mesoscale and Nanoscale Physics · Physics 2014-07-08 Hatice Unal , Oguz Gulseren , Sinasi Ellialtioglu , Ersen Mete

We have successfully obtained a ZnO/ZnS heterostructure by heating a ZnS(001) single crystal in a controlled impurities-free oxygen atmosphere. Combining X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM), we explore…

Materials Science · Physics 2026-01-21 P. R. A de Oliveira , I. Coelho , G. Felix , P. Venezuela , F. Stavale

I present a theory of electron dynamics in semiconductors with slowly varying composition. I show that the frequency-dependent conductivity, required for the description of transport and optical properties, can be obtained from a knowledge…

Condensed Matter · Physics 2016-08-31 Michael R. Geller

Recent photoemission experiments on the Si(553)-Au reconstruction show a one-dimensional band with a peculiar ~1/4 filling. This band could provide an opportunity for observing large spin-charge separation if electron-electron interactions…

Materials Science · Physics 2009-11-11 Sampsa Riikonen , Daniel Sanchez-Portal

We demonstrate the accuracy of the hybrid functional HSE06 for computing band offsets of semiconductor alloy heterostructures. The highlight of this study is the computation of conduction band offsets with a reliability that has eluded…

Materials Science · Physics 2015-05-19 Amita Wadehra , Jeremy W. Nicklas , John W. Wilkins

We develop a unified numerical approach for modeling semiconductor-superconductor heterostructures. Our approach takes into account on equal footing important key ingredients: proximity-induced superconductivity, orbital and Zeeman effect…

The improvement of light absorption in Si/BeSe$_{0.41}$Te$_{0.59}$ heterostructures for solar cell applications is studied theoretically. First, using simple approaches we found that light absorption could be improved in a single…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 T. Sandu , W. P. Kirk