Sökning: "surface states"

Visar resultat 1 - 5 av 363 avhandlingar innehållade orden surface states.

  1. 1. Topology Meets Frustration : Exact Solutions for Topological Surface States on Geometrically Frustrated Lattices

    Författare :Flore Kiki Kunst; Emil Bergholtz; Jack Lidmar; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Topology; boundary states; surface states; edge states; Chern insulator; Weyl semimetal; Theoretical Physics; teoretisk fysik;

    Sammanfattning : One of the main features of topological phases is the presence of robust boundary states that are protected by a topological invariant. Famous examples of such states are the chiral edge states of a Chern insulator, the helical edge states of a two-dimensional Z2 insulator, and the Fermi arcs of Weyl semimetals. LÄS MER

  3. 2. Electronic states of adsorbates and insulating overlayers on metal surfaces

    Författare :Fredrik Olsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Shockley surface states; local density of states; scanning tunneling microscope; chemisorption; sodium chloride; noble metals; image states; electronic states; density functional theory;

    Sammanfattning : Electronic states of adsorbates and insulating overlayers provide a wealth of scientifically interesting phenomena with great technological importance. Interesting phenomena arise, for example, from the interaction of electronic states of an adsorbate with the continuum of metal electron states, both propagating bulk states and surface states. LÄS MER

  4. 3. Methods for Characterization and Optimization of AlGaN/GaN HEMT Surface Passivation

    Författare :Martin Fagerlind; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; surface states; surface passivation; annealing; processing; AlGaN GaN HEMT; MIS-capacitor;

    Sammanfattning : The Gallium Nitride based high electron mobility transistor is rapidly improving and is emerging as a viable alternative for use in high power applications operating in the microwave frequency domain. The suitability of the AlGaN/GaN material system is due to the possibility to grow epitaxial heterostructures that provide; high electron mobility, high electron saturation velocity, high carrier density and a high dielectric breakdown field. LÄS MER

  5. 4. Consequences of a non-trivial band-structure topology in solids : Investigations of topological surface and interface states

    Författare :Magnus H. Berntsen; Oscar Tjernberg; Philip Hofmann; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; spin- and angle-resolved photoelectron spectroscopy; time-of-flight analyzer; laser based light source; topological insulator; topological crystalline insulator; thin films; surface state; interface state; Bi2Se3; Pb1-xSnxSe;

    Sammanfattning : The development and characterization of experimental setups for angle-resolved photoelectron spectroscopy (ARPES) and spin- and angle-resolved photoelectron spectroscopy (SARPES) is described. Subsequently, the two techniques are applied to studies of the electronic band structure in topologically non-trivial materials. LÄS MER

  7. 5. Surface analysis of low dimensional materials : revealing their electronic properties by advanced spectroscopy

    Författare :Vladimir Miranda la Hera; Thomas Wågberg; Eduardo Gracia-Espino; Tomas Edvinsson; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Low-dimensional materials; surface science; surface-sensitive techniques; angle-resolved photoemission spectroscopy; ultraviolet photoemission spectroscopy; electronic properties;

    Sammanfattning : Low-dimensional materials (0D, 1D, 2D) have been widely used to develop modern miniaturized (micro- and nano-) technology. The use of these materials come from their extraordinary optical, electrical, thermal, and mechanical properties, which are very different from the bulk crystal. LÄS MER