Sökning: "Kondenserade materians fysik"

Hittade 4 avhandlingar innehållade orden Kondenserade materians fysik.

1. 1. Modeling of non-equilibrium scanning probe microscopy

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

   Sammanfattning : 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. LÄS MER

3. 2. Theoretical modeling of scanning tunneling microscopy

   Författare :Alexander Gustafsson; Magnus Paulsson; Jorge Iribas Cerdá; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Scanning tunneling microscopy; Computational models; Quantum tunneling; Green s functions; Density functional theory; Condensed Matter Physics; Kondenserade materians fysik;

   Sammanfattning : The main body of this thesis describes how to calculate scanning tunneling microscopy (STM) images from first-principles methods. The theory is based on localized orbital density functional theory (DFT), whose limitations for large-vacuum STM models are resolved by propagating localized-basis wave functions close to the surface into the vacuum region in real space. LÄS MER

4. 3. Magnetic solotronics near the surface of a semiconductor and a topological insulator

   Författare :Mohammad Reza Mahani; C.M. Canali; Biplab Sanyal; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetic solotronics; Transition metal dopants; Dilute magnetism in semiconductors and topological insulators; Atomistic tight-binding models; DFT; Spin dynamics; Magnetic anisotropy; Scanning tunneling microscope.; Condensed Matter Physics; Kondenserade materians fysik;

   Sammanfattning : Technology where a solitary dopant acts as the active component of an opto-electronic device is an emerging  field known as solotronics, and bears the promise to revolutionize the way in which information is stored, processed and transmitted. Magnetic doped semiconductors and in particular (Ga, Mn)As, the archetype of dilute magnetic semiconductors, and topological insulators (TIs), a new phase of quantum matter with unconventional characteristics, are two classes of quantum materials that have the potential to advance spin-electronics technology. LÄS MER

5. 4. Topological Phase Transitions in Magnetic Nanostructures of Dirac Materials

   Författare :Nezhat Pournaghavi; Carlo M. Canali; Michael Flatté; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Topological insulators; Magnetic materials; Quantum anomalous Hall effect; Topological magneto electric effect; Dirac semimetals; Weyl semimetals; Condensed Matter Physics; Kondenserade materians fysik;

   Sammanfattning : Over the past two decades, the discovery of topological Dirac materials, such as topological insulators and semimetals, has defined a new paradigm in condensed matter physics and established new platforms for realizing spin electronic devices and quantum computing. The novel quantum properties of these materials, which are mainly due to the presence of strong spin-orbit coupling, are invariant under topological transformations, making them more resilient to structural disorder, electromagnetic and thermal fluctuations in comparison to the conventional silicon-based materials. LÄS MER