Search for dissertations about: "Current density functional theory"

Showing result 6 - 10 of 63 swedish dissertations containing the words Current density functional theory.

2. 6. Computer Simulations in Materials Physics: Time-scales and Accuracy

   Author : Urban Engberg; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; basis sets; computer simulations; pseudopotentials; materials physics; density functional theory; transition state theory; O N ; quantum Monte Carlo;

   Abstract : Computer simulations are expected to play an increasingly important role within materials physics in the future. Owing to a combination of accurate physical approximations, improved implementations of these approximations, and the exponentially increasing power of computers, problems can now be solved on length and time-scales which were unimaginable only a decade ago. READ MORE

4. 7. Interactions and Interference in Mesoscopic Systems: Josephson Current through Quantum Dots and Josephson Junction Arrays

   Author : Klas Engström; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; density functional theory; quantum dots; Josephson effect; Andreev reflection; mesoscopic superconductivity; Josephson junction array; coulomb interactions; Bogoliubov-de Gennes equation; quantum phase transition;

   Abstract : The focus of the thesis is on the interplay between interactions and interference effects in mesoscopic systems. More specifically, the two main projects included deal with Coulomb interactions and Josephson effect in two superconductor-normal metal systems: (i) a Josephson junction array and (ii) a superconductor-normal metal-superconductor (SNS) system in which the normal part is a quantum dot. READ MORE

5. 8. Dynamics and Fluctuations in Single-Electron Tunneling Devices

   Author : Niklas Dittmann; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; quantum dot; time-dependent density-functional theory; perturbation theory; single-electron source;

   Abstract : In recent years, it has been routinely achieved to build nanoscale electronic devices, which generate current pulses carrying only a single elementary charge. Realizations of these single-electron emitters are based on time-dependently driven quantum dots, on single-electron turnstiles built from superconductor/normal-metal hybrid structures, and also on nanosystems employing Lorentzian voltage pulses or surface acoustic waves. READ MORE

6. 9. Non-equilibrium fermions within lattice density functional theory: quantum transport and ultracold-atom phenomena

   Author : Alexey Kartsev; Matematisk fysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Fysicumarkivet A:2013:Kartsev;

   Abstract : Cutting-edge technology needs small, ultrafast devices, operational in a wide range of regimes. This calls for solids with novel, unconventional and tailorable properties. Great progress is expected from materials in which electron-electron and electron-phonon correlations strongly affect the dynamics ( i.e. READ MORE

7. 10. Modeling of non-equilibrium scanning probe microscopy

   Author : Alexander Gustafsson; Magnus Paulsson; Tchavdar Todorov; Linnéuniversitetet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; scanning tunneling microscopy; molecular dynamics; density functional theory; non-equilibrium Green s functions; Condensed Matter Physics; Kondenserade materians fysik;

   Abstract : The work in this thesis is basically divided into two related but separate investigations.The first part treats simple chemical reactions of adsorbate molecules on metallic surfaces, induced by means of a scanning tunneling probe (STM). The investigation serves as a parameter free extension to existing theories. READ MORE