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We report on a combined photoluminescence imaging and atomic force microscopy study of single, isolated self-assembled InAs quantum dots (density <0.01 um^(-2) capped by a 95 nm GaAs layer, and emitting around 950 nm. By combining optical…

Mesoscale and Nanoscale Physics · Physics 2017-07-27 Luca Sapienza , Jin Liu , Jin Dong Song , Stefan Falt , Werner Wegscheider , Antonio Badolato , Kartik Srinivasan

I formulate a general finite element method (FEM) for self-gravitating stellar systems. I split the configuration space to finite elements, and express the potential and density functions over each element in terms of their nodal values and…

Instrumentation and Methods for Astrophysics · Physics 2015-05-18 Mir Abbas Jalali

Atomic effective pseudopotentials enable atomistic calculations at the level of accuracy of density functional theory for semiconductor nanostructures with up to fifty thousand atoms. Since they are directly derived from ab-initio…

Materials Science · Physics 2024-03-14 Surender Kumar , Hanh Bui , Gabriel Bester

The magnetic properties of hole quantum dots in Ge are sensitive to their shape due to the interplay between strong spin-orbit coupling and confinement. We show that the split-off band, surrounding SiGe layers, and hole-hole interactions…

Mesoscale and Nanoscale Physics · Physics 2024-08-27 Mitchell Brickson , N. Tobias Jacobson , Andrew J. Miller , Leon N. Maurer , Tzu-Ming Lu , Dwight R. Luhman , Andrew D. Baczewski

The possibility of a novel type of semiconductor quantum dots obtained by spatially modulating the spin-orbit coupling intensity in III-V heterostructures is discussed. Using the effective mass model we predict confined one-electron states…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 M. Valin-Rodriguez , A. Puente , L. Serra

It has been recently shown that a nanostructure composed of a quantum dot surrounded by a quantum ring possesses a set of very unique characteristics that make it a good candidate for future nanoelectronic devices. Its main advantage is the…

Mesoscale and Nanoscale Physics · Physics 2016-04-15 Iwona Janus-Zygmunt , Barbara Kedzierska , Anna Gorczyca-Goraj , Elzbieta Zipper , Maciej M. Maska

In nodal based finite element method (FEM), degrees of freedom are associated with the nodes of the element whereas, for edge FEM, degrees of freedom are assigned to the edges of the element. Edge element is constructed based on Whitney…

Numerical Analysis · Mathematics 2022-03-29 Durgarao Kamireddy , Saurabh Madhukar Chavan , Arup Nandy

Precise control of the properties of semiconductor quantum dots (QDs) is vital for creating novel devices for quantum photonics and advanced opto-electronics. Suitable low QD-density for single QD devices and experiments are challenging to…

In bilayer graphene the exact energy levels of quantum dots can be derived from the four-component continuum Hamiltonian. Here, we study the quantum dot energy levels with approximate equations and compare them with the exact levels. The…

Mesoscale and Nanoscale Physics · Physics 2025-11-03 G. Giavaras

We study the electronic and magnetic properties of multilayer quantum dots (MQDs) of graphite in the nearest-neighbor approximation of tight-binding model. We calculate the electronic density of states and orbital susceptibility of the…

Mesoscale and Nanoscale Physics · Physics 2015-01-19 Hazem Abdelsalam , Tania Espinosa-Ortega , Igor Lukyanchuk

A quasimodal expansion method (QMEM) is developed to model and understand the scattering properties of arbitrary shaped two-dimensional (2-D) open structures. In contrast with the bounded case which have only discrete spectrum (real in the…

We introduce an efficient finite-element approach for large-scale real-space pseudopotential density functional theory (DFT) calculations incorporating noncollinear magnetism and spin-orbit coupling. The approach, implemented within the…

Materials Science · Physics 2025-06-11 Nikhil Kodali , Phani Motamarri

A set of theoretical results [1-10] is reviewed, which concern calculations of energy spectra, density of energy levels, spin polarization, transport and optical properties (infrared absorption, luminescence) of semiconductor quantum dots…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Augusto Gonzalez

Highly accurate experimental structure factors of silicon are available in the literature, and these provide the ideal test for any \emph{ab initio} method for the construction of the all-electron charge density. In a recent paper [J. R.…

Materials Science · Physics 2015-05-14 J. R. Trail , D. M. Bird

Atomistic electronic structure calculations are performed to study the coherent inter-dot couplings of the electronic states in a single InGaAs quantum dot molecule. The experimentally observed excitonic spectrum [12] is quantitatively…

Mesoscale and Nanoscale Physics · Physics 2013-08-01 Muhammad Usman , Yui-Hong Matthias Tan , Hoon Ryu , Shaikh S. Ahmed , Hubert Krenner , Timothy B. Boykin , Gerhard Klimeck

We develop a systematic approach to determine and measure numerically the geometry of generic quantum or "fuzzy" geometries realized by a set of finite-dimensional hermitian matrices. The method is designed to recover the semi-classical…

High Energy Physics - Theory · Physics 2016-06-22 Lukas Schneiderbauer , Harold C. Steinacker

Recent advances in nanotechnology have enabled researchers to manipulate small collections of quantum mechanical objects with unprecedented accuracy. In semiconductor quantum dot qubits, this manipulation requires controlling the dot…

Mesoscale and Nanoscale Physics · Physics 2019-03-06 Adam Frees , John King Gamble , Daniel R. Ward , Robin Blume-Kohout , M. A. Eriksson , Mark Friesen , S. N. Coppersmith

We investigate the convergence of quasi-particle energies for periodic systems to the thermodynamic limit using increasingly large simulation cells corresponding to increasingly dense integration meshes in reciprocal space. The…

The confinement mechanism of electrons in gated circular quantum dots is studied in a sequence of models, from self-consistent 3D Hartree calculations to the semiclassical model of Shikin et al. Separation of the vertical from transverse…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 J. Martorell , D. W. L. Sprung

In this work, the changes in the energy of electrons and holes, oscillator strength and interband transition time when external fields are applied to a GaAs/AlGaAs semiconductor double ring grown by the droplet epitaxy technique are…

Computational Physics · Physics 2023-09-11 Adrian Radu , Cristina Stan , Doina Bejan