Category Physics

Experimental and calculated structure of the Fermi surface and band dispersion of PtSn4.

Physicists have discovered a topological metal, PtSn4 (platinum and tin), with a unique electronic structure that may someday lead to energy efficient computers with increased processor speeds and data storage. The electrons in topological quantum materials can travel close to speed of light thanks to unique property Dirac dispersion. Up until now, only isolated points, called Dirac points, with relatively small numbers of conduction electrons, were known to exist in such materials. In PtSn4, the scientists not only discovered a high density of conduction electrons, but also large number of closely positioned Dirac points forming extended lines or Dirac node arcs.

Kaminski and his ARPES equipment.

“Thi...

Applying a magnetic field to PdCoO2, a non-magnetic metal, made it conduct 70% more electricity, even though basic physics principles would have predicted the opposite. Credit: Eiri Ono/Kyoto University

Applying a magnetic field to a non-magnetic metal made it conduct 70% more electricity, even though basic physics principles would have predicted the opposite. Insights from pure mathematics are lending new insights to material physics, which could aid in development of new devices and sensors. “We never expected that magnetoresistance could be lowered even further in the compound we tested, because in theory it should have increased,” says Kyoto University study author Shingo Yonezawa.

Applying a magneticfield to metals affects how well they are able to conduct electricity...

Single nanocrystal spectroscopy identifies the interaction between zero-dimensional CdSe/ZnS nano crystals (quantum dots) and two-dimensional layered tin disulfide as a non-radiative energy transfer, whose strength increases with increasing number of tin disulfide layers. Such hybrid materials could be used in optoelectronic devices such as photovoltaic solar cells, light sensors, and LEDs. Credit: Brookhaven National Laboratory

It paves the way for better optoelectronic apps eg energy-harvesting photovoltaics, light sensors, LEDs. Scientists combined excellent light-harvesting properties of quantum dots with the tunable electrical conductivity of a layered tin disulfide semiconductor...

Magnetic order in (Sr,Na)Fe2As2: The crystal structure contains planes of iron atoms (shown as red spheres). Half the iron sites have a magnetization (shown as red arrows), which points either up or down, but the other half have zero magnetization. This shows that the magnetism results from the constructive and destructive interference of two magnetization waves, a clear sign that the magnetic electrons are itinerant, which means they are not confined to a single site. The same electrons are responsible for the superconductivity at lower temperature. Credit: Image courtesy of DOE/Argonne National Laboratory

Scientists have discovered only half the atoms in some iron-based superconductors are magnetic, providing the first conclusive demonstration of the wave-like properties of metallic magn...