Sökning: "Tight-Binding"

Visar resultat 1 - 5 av 27 uppsatser innehållade ordet Tight-Binding.

1. 1. The effect of disorder on the axial anomaly in a lattice model in 1 + 1 dimensions

   Master-uppsats, KTH/Fysik

   Författare :Agnes Wattrang; [2023]
   Nyckelord :Axial anomaly; tight-binding model; semiclassical physics; correlated disorder.; Axial kiral anomali; tätbindningsmodell; semiklassisk fysik; korrelerad oordning;

   Sammanfattning : This work investigates the effect of a disorder potential, that represents impurities/dislocations in the lattice, on the time-dependent signature of the axial anomaly in a one-band tight-binding model in one spatial dimension. The tight-binding model is solved numerically and the simulation results are compared with a semiclassical expression for the time-dependent axial density, n5(t), due to Nielsen and Ninomiya [1]. LÄS MER

3. 2. Quantum Transport in Topological Insulator Nanowires

   Master-uppsats, KTH/Fysik

   Författare :Sergi Pradas Rodriguez; [2023]
   Nyckelord :quantum transport; topological insulators; nanowires; numerical analysis; Kwant; etc.; kvanttransport; topologiska isolatorer; nanotrådar; numerisk analys; Kvant; etc.;

   Sammanfattning : Three-dimensional topological insulators are materials that have a bulk band gap like a traditional insulator, but which hold topologically protected conducting surface states. In this thesis we present a numerical analysis of the surface states of topological insulator nanowires in the tight-binding approximation. LÄS MER

4. 3. Investigation of a newrepresentation of spin

   Kandidat-uppsats, Uppsala universitet/Materialteori

   Författare :Minna Palmgren Thun; [2023]
   Nyckelord :Material theory; Spin; Statistical physics; Second quantization; Materialteori; spinn;

   Sammanfattning : The Bose-Hubbard Model, a tight binding model within solid state theory can be solved exactly using a number theoretical approach. From this approach, in the two sited Bose-Hubbard model, the hopping term in the model takes the form of a Pauli x matrix. The hopping term can be interpreted as a two energy level system or a dimer with k+1 particles. LÄS MER

5. 4. Monte Carlo study of disorder in electronic tight-binding models

   Kandidat-uppsats, Lunds universitet/Fysiska institutionen; Lunds universitet/Matematisk fysik

   Författare :Carl Pettersson; [2023]
   Nyckelord :Monte Carlo; Tight-binding model; Falicov-Kimball model; Physics and Astronomy;

   Sammanfattning : Oftentimes solids are described by uniform, periodic lattices. In reality, however, there is often some disorder on some of the sites in the lattice. This disorder may come from, for example, there being a different type of atom or tightly bound electrons resulting in a larger on-site potential, affecting the electronic properties of the lattice. LÄS MER

7. 5. Wannier Functions in non-Hermitian Systems

   Master-uppsats, KTH/Fysik

   Författare :Alberto Zorzato; [2022]
   Nyckelord :Theoretical Physics; Condensed Matter Physics; non-Hermitian Systems; Wannier Functions;

   Sammanfattning : The scope of this thesis is analyzing and characterizing certain gapless states in tight-binding non-Hermitian systems. We start by providing a pedagogical introduction to tight-binding theory, topological phases of matter, Wannier functions as real-space duals of Bloch functions and their properties, non-Hermitian systems and associated differences from standard Hermitian systems. LÄS MER