Concept

Semimétal

Publications associées (107)

Tailoring band gaps of insulators by adsorption at surface defects: Benzoic acids on NaCl surfaces

The adsorption of benzoic acid and its OH-substituted derivatives, namely, salicylic acid (SA) and parasalicylic acid on various NaCl surfaces has been investigated by density-functional theory with hybrid exchange-correlation functional. The ideal NaCl (1 ...

2009

Photoinduced electron transfer from a terrylene dye to TiO2: Quantification of band edge shift effects

Felix Thomas Eickemeyer, Ulf Anders Hagfeldt

A terrylene chromophore exhibiting a high extinction coeff. has been developed as a sensitizer for photovoltaic applications. The photophys. and photochem. properties of the dye were analyzed both exptl. and theor. Terrylene-sensitized nanocryst. TiO2 sola ...

2009

Negative plasmon dispersion in the transition-metal dichalcogenide 2H-TaSe2

Helmuth Berger

We report about an electron energy-loss study on the dispersion of the charge-carrier plasmon in the charge-density-wave system 2H-TaSe2 above and below the metal-insulator transition. In both cases we find a negative slope, which is in remarkable contrast ...

2009

Conduction in rectangular quasi-one-dimensional and two-dimensional random resistor networks away from the percolation threshold

Jürgen Brugger, Luis Guillermo Villanueva Torrijo, Thomas Kiefer

In this study we investigate electrical conduction in finite rectangular random resistor networks in quasione and two dimensions far away from the percolation threshold p(c) by the use of a bond percolation model. Various topologies such as parallel linear ...

American Physical Society2009

Metal-insulator transition in graphite: A comparison to heterostructures with high carrier mobility

Dirk Grundler

Conditions for a transition from the insulator (I) to metal (M) state in the electron system of highly oriented pyrolytic graphite (HOPG) have been studied by means of magnetotransport measurements in a broad temperature range (0.3–150 K). In magnetic fiel ...

2008

Band gap opening at the 6H-SiC(0001) surface passivated by an epitaxial silicon oxynitride layer: A first-principles investigation

Alfredo Pasquarello, Fabien Devynck

Using hybrid density functionals, we investigate the origin of the large band gap experimentally observed at the 6H-SiC(0001) surface when passivated by an epitaxial silicon oxynitride layer. In order to distinguish the effects resulting from the interfaci ...

2008

Towards a nanostructured thermoelectric generator using ion-track lithography

Arnaud Bertsch, Xuan Li

This paper presents the process development towards a new generation of nanostructured thermoelectric generators for power harvesting from small temperature gradients by using a combination of traditional silicon microfabrication techniques, electroplating ...

2008

Photoemission and optical studies of ZrSe3, HfSe3, and ZrS3

Marco Grioni, Helmuth Berger, Daniela Pacilè

Angle-resolved photoemission spectroscopy (ARPES) and optical measurements were performed on single crystal samples of ZrSe3, HfSe3, and ZrS3, which belong to the class of low-dimensional band insulators. By ARPES, we traced the dispersion of the (S 3p, Se ...

2007

MICROFABRICATED HALL SENSORS MINIATURIZED TO THE NANOMETER SCALE

Jürgen Brugger, Giovanni Boero, Radivoje Popovic, Christian Santschi, Schahrazede-Lila Mouaziz

The aim of the project is the development of a new technology for the fabrication of bismuth (Bi) micro-nano Hall sensors integrated on plastic cantilevers. Bi, a semi-metal, is deposited by evaporation and structured by lift-off. Four electrodes made with ...

2006

Understanding mixed valent materials: Effects of dynamical core-hole screening in high-pressure x-ray spectroscopy

Marco Grioni

Changes in the electronic structure of Yb, a material whose valence is modified under pressure, are observed with remarkable detail in x-ray absorption and emission data measured between ambient conditions and 20 GPa. These changes are reproduced by a theo ...

2006

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