Archive for new materials
Electrons flowing swiftly across the surface of topological insulators (TIs) are “spin polarized,” their spin and momentum locked. This new way to control electron distribution in spintronic devices makes TIs a hot topic in materials science. Now Berkeley Lab scientists have discovered more surprises: contrary to assumptions, the spin polarization of photoemitted electrons from a topological insulator is wholly determined in three dimensions by the polarization of the incident light beam.
In bulk, topological insulators (TIs) are good insulators, but on their surface they act as metals, with a twist: the spin and direction of electrons moving across the surface of a TI are locked together. TIs offer unique opportunities to control electric currents and magnetism, and new research by a team of scientists from China [...]
Space-age ceramics at their best promise advanced jet and gas turbine engines that burn with greater fuel efficiencies and less pollution. Berkeley Lab scientists have developed the first mechanical test rig for obtaining real-time X-ray computed microtomography images at ultrahigh temperatures for improving the composition and architecture of advanced ceramic composites.
Using a new technique called HARPES, for Hard x-ray Angle-Resolved PhotoEmission Spectroscopy, Berkeley Lab researchers have unlocked the ferromagnetic secrets of dilute magnetic semiconductors, materials of great interest for spintronic technology.
New findings from a team of Berkeley Lab and Japanese scientists suggest that the road to magnetic vortex RAM might be more difficult to navigate than previously supposed, but there might be unexpected rewards as well. A study at the Advanced Light Source revealed that contrary to suppositions, the formation of magnetic vortices in ferromagnetic nanodisks is an asymmetric phenomenon.
Using ultrafast lasers, Berkeley Lab scientists have tackled the long-standing mystery of how Cooper pairs form in high-temperature superconductors. With pump and probe pulses spaced just trillionths of a second apart, the researchers used photoemission spectroscopy to map rapid changes in electronic states across the superconducting transition, revealing relationships of energy and momentum never seen before in these promising, but stubborn, complex materials.
Beyond the High-Speed Hard Drive: Topological Insulators Open a Path to Room-Temperature Spintronics
Berkeley Lab theorists and experimenters have led in the exploration of the unique properties of topological insulators, where electrons may flow on the surface without resistance but with their spin orientations and directions intimately related. Recent research at beamline 12.0.1 of the Advanced Light Source opens the way to exciting prospects for practical new spintronic devices that exploit control of electron spin as well as charge.