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Phonon Polariton Behavior in 2D Materials

Synchrotron infrared nanospectroscopy (SINS) was used to study the behavior of phonon polaritons in ultrathin crystals of hexagonal boron nitride. The results pave the way towards engineering infrared-light photonic nanodevices and expand our understanding of polariton behavior in low-dimensional nanomaterials. Read more »PPT-icon-35 PDF-icon-35

ALSNews Vol. 368

ALSNews Monthly Newsletter of the Advanced Light Source, Lawrence Berkeley National Laboratory Weyl Fermions Discovered After 85 Years 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,Read More Read more »

ALSNews Vol. 367

ALSNews Monthly Newsletter of the Advanced Light Source, Lawrence Berkeley National Laboratory A Designed Protein Maps Brain Activity Scientists designed and validated via crystallographic studies a fluorescent protein that allows the permanent marking of active brain cells. The protein was then used to study live changes via fluorescence in the active nerve cells in brainsRead More Read more »

Misfolded opsin mutants display elevated β-sheet structure

Mutations in rhodopsin can cause misfolding and aggregation of the receptor, which leads to retinitis pigmentosa, a progressive retinal degenerative disease. Förster resonance energy transfer (FRET) and Fourier transform infrared (FTIR) microspectroscopy were utilized to probe within cells the structures formed by G188R and P23H opsins. Read more »

Wolfgang Eberhardt on Light Sources: Getting the Balance Right

Wolfgang Eberhardt, an internationally respected expert on synchrotrons, is wrapping up an extended visit to the ALS. Between experiments furthering our understanding of organic solar-cell materials, he discusses the relative merits of diffraction-limited storage rings (such as the proposed ALS upgrade, ALS-U) and free-electron laser facilites. Read more »

ALSNews Vol. 366

ALSNews Monthly Newsletter of the Advanced Light Source, Lawrence Berkeley National Laboratory Signal Speed in Nanomagnetic Logic Chains A time-resolved x-ray imaging technique directly observes signal propagation dynamics in nanomagnetic logic (NML) chains. The technique can assess NML reliability on fast timescales and help optimize chain engineering for this promising ultralow-power computing architecture. Read more…Read More Read more »

Carotenoid Pigment Is the Key to Photoprotection

A technique newly available at the ALS has enabled the discovery of a surprising key event in photosynthetic systems. A protein shifting from an “orange” light-absorbing state to a “red” photoprotective state turns out to be an unanticipated molecular priming event in photoprotection. Read more »PPT-icon-35

Narrowly Distributed Crystal Orientation in Biomineral Vaterite

The cover shows a scanning electron micrograph of vaterite crystals formed by the sea squirt Herdmania momus. These are the largest single crystals of vaterite ever observed, including biogenic, geologic or synthetic vaterite. Flat crystal faces are uncommon in biogenic crystals, but these crystals are clearly hexagonal pyramids. Pokroy et al. show that these crystals have smooth fracture surfaces; thus, they most likely formed ion-by-ion, rather than by attachment of particles. Narrowly distributed orientations and lack of organics at crystal interfaces suggest a new mechanism of biomineral crystal growth, perhaps spherulitic growth from solution. Read more »

Tracking the Elusive QOOH Radical

For the first time, researchers directly observed QOOH molecules, a class of highly reactive molecules at the center of the web of ignition chemistry reactions. The data generated will improve the fidelity of combustion models used to create cleaner and more efficient cars and trucks. Read more »PPT-icon-35 PDF-icon-35