Sökning: "magnetic semiconductors"

Visar resultat 16 - 20 av 52 avhandlingar innehållade orden magnetic semiconductors.

1. 16. Magnetism of manganites, semiconductors and spin glasses

   Författare :Roland Mathieu; Ian Campbell; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; Materialvetenskap; Materials science; Teknisk materialvetenskap; fasta tillståndets fysik; Solid State Physics;

   Sammanfattning : Magnetic and electrical properties of selected compounds containing manganese (Mn) are investigated by SQUID magnetometry and transport measurements.(Ga,Mn)As is a magnetic semiconductor obtained from GaAs by substituting Ga3+ for Mn2+. Mn acts in the alloy as a magnetic impurity, as well as a hole dopant. LÄS MER

3. 17. Quantum electronic transport in low-dimensional semiconductors

   Författare :Heiner Linke; Fasta tillståndets fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum transport; two-dimensional electron gas; contact-free characterisation; ballistic transport; mesoscopic; electron billiard; quantum dot; electron-electron interaction; non-linear; phase breaking; Halvledarfysik; Fysicumarkivet A:1997:Linke; non-symmetric conductio; Semiconductory physics; low-dimensional structures;

   Sammanfattning : Electronic transport is studied at low temperatures in two-dimensional electron gases (2DEGs) and in mesoscopic semiconductor microstructures. The method of microwave-detection of the Shubnikov-de Haas effect for the contact-free characterisation of transport properties of 2DEGs is explored using both magnetic-field modulation and light-induced carrier modulation. LÄS MER

4. 18. Interactions, initial states, and low-dimensional semiconductors

   Författare :Peter Jaksch; Stephanie M. Reimann-Wacker; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Q!uantum mechanical interactions; quantum point contact QPC ; quantum wires; exchange-correlation energy; Reilly model; quantum algorithms; Physics; Fysik;

   Sammanfattning : This thesis is concerned with different aspects of quantum mechanical interactions. The first part of the thesis focuses on their effects in low-dimensional semiconductors; the second part on one of their applications: quantum algorithms, which utilize superpositions created from quantum mechanical interactions. LÄS MER

5. 19. Density Functional Theory in Computational Materials Science

   Författare :Jorge Mario Osorio Guillén; Rajeev Ahuja; Börje Johansson; Bruce N. Harmon; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Density Functional Theory; High Pressure; Phase Transitions; Elastic Properties; Lithium Batteries; Dilute Magnetic Semiconductors; Fysik; Physics; Fysik;

   Sammanfattning : The present thesis is concerned to the application of first-principles self-consistent total-energy calculations within the density functional theory on different topics in materials science. Crystallographic phase-transitions under high-pressure has been study for TiO2, FeI2, Fe3O4, Ti, the heavy alkali metals Cs and Rb, and C3N4. LÄS MER

7. 20. Point defect interactions and structural stability of compounds

   Författare :Vitaly Baykov; Börje Johansson; Peter Mohn; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; first principles; ab initio; density functional theory; point defects interactions; diluted magnetic semiconductors; structural stability; zirconium alloys; Other materials science; Övrig teknisk materialvetenskap;

   Sammanfattning : Theoretical studies of point defect interactions and structural stability of compounds have been performed using density functional theory. The defect-related properties, such as activation energy of diffusion, electronic and magnetic structure of selected materials have been studied. LÄS MER