A small amount of compressive strain turns a nonmetallic form of tin into a 3D topological Dirac semimetal—a kind of “supermetal” with very high electron mobility. With its rich topological phase diagram, the material shows promise for both novel physics and eventual device applications. Read more »
ALS Work Using ARPES
Angle-resolved photoemission spectroscopy (ARPES) is a technique in which a highly focused beam of x-rays is used to kick electrons out of the sample. By analyzing the ejected electrons' direction and energy, the researchers can obtain the material's band structure—a map of the electrons' behavior in the material.
Researchers report on angle-resolved photoemission spectroscopy (ARPES) measurements performed on the transition-metal oxide V2O3. The results overturn a decade-old theory about metal-to-insulator transitions in this material and provide a spectroscopic benchmark test for future models. Read more »
ARPES directly reveals for the first time how electronic states are altered when epitaxial graphene is deposited on a substrate of hexagonal boron nitride (h-BN). The interaction between the materials in this heterostructure greatly improves its suitability for advanced, ultralow-power device applications. Read more »
This September, Beamline 7.0.2, MAESTRO, will accept general user proposals for the first time. Its unique attributes combine strong sample preparation capabilities with cutting-edge spectromicroscopy tools, offering researchers unparalleled opportunities for studying the correlation between structure and electronic properties. Read more »
The tantalizing prospect of energy-saving, ultralow-power electronics has led to a vigorous search for optimal topological insulator materials. Now, an international team of scientists has discovered the first of a new class of topological insulators with unique properties: quasi-1D bismuth iodide. Read more »
Scientists have been researching high-temperature (high-Tc) superconductors for decades with the goal of finding materials that express superconducting capabilities at room temperature, which would be a requirement for practical and cost-effective applications. The newest materials to gain scientific interest are iron-based superconductors, and the latest research from the ALS on these materials indicates a new factor that determines their superconductivity. Read more »
Weyl fermions, elusive massless particles first theorized 85 years ago, have now been detected as emergent quasiparticles in synthetic crystals of the semimetal TaAs. The discovery could allow for the nearly free and efficient flow of electricity, as well as the realization of many fascinating topological quantum phenomena.
A team of researchers using angle-resolved photoemission spectroscopy (ARPES) at ALS Beamline 10.0.1 found intriguing particles in a new phase of quantum matter: topological Weyl semimetals.
Read more »
We are looking forward to an exciting and productive year at the ALS, with plans for new beamlines and capabilities coming online, and more users taking advantage of our technical and scientific expertise to produce a record number publications. At the ALS, we are encouraged by this year’s funding and are looking for new ways to focus on our core strengths while expanding partnerships to explore new opportunities. Read more »
All superconducting cuprates share a common structure: charge reservoirs stacked between layers of CuO2. An undoped version, including only C and O, is not available in nature. By growing epitaxial films with a pulsed-laser deposition facility, researchers stabilized a 2D version of CuO, which can be thought as composed by two CuO2 planes staggered and superposed.