Science Highlights

Nickel monosilicide (NiSi), a material widely used to connect transistors in semiconductor circuits, was wrongly predicted by theory to be non-magnetic. Now scientists have used neutron scattering to identify an elusive form of magnetic order in NiSi. This finding could lead to improved semiconductors for computers and computer memory.

The Facility for Rare Isotope Beams (FRIB) has discovered five never-before-seen heavy element isotopes: thulium-182 and 183, ytterbium-186 and 187, and lutetium-190. Researchers found the new isotopes in the debris of collisions between a stable beam of platinum-198 and a carbon target. These results show the potential for FRIB as it increases its capabilities.

The interactions of protons and neutrons can be too complex to model using conventional computers and quantum computers face reliability issues. This research combined conventional computers and quantum computers to simulate the scattering of two neutrons. This opens a path to computing nuclear reaction rates for situations that are difficult or impossible to measure in a laboratory.

Computational scientists at the Department of Energy’s Oak Ridge National Laboratory have published a study in the Journal of Chemical Theory and Computation that questions a long-accepted factor in simulating the molecular dynamics of water: the 2 femtosecond (one quadrillionth of a second) time step. 

Theoretical models of dark matter predict that its signals can be detected using low-background radiation detectors. By looking for specific types of dark matter and finding no signal, scientists operating the Majorana Demonstrator experiment have significantly narrowed the characteristics of potential dark matter particles. The results will help design future experiments.

Potassium-40 usually decays to calcium-40, but about 10 percent of the time it decays to argon-40 through electron capture. One variant of this decay path ends in argon-40 in its ground state. The rate of this decay is important for using argon-40 to determine the age of geologic features and studying neutrinoless double beta decay. Researchers recently made the first direct observations of this very rare but critical decay path.

Conventional metals cannot conduct light in their interiors, but scientists have discovered that in the quantum metal ZrSiSe, electrons can give rise to plasmons. These are collective oscillations in a material that are strong and long lived, and they can combine with photons to form new modes called polaritons that can carry photons along zig-zag paths in the material.