Highlights

The Wisconsin MRSEC has created thin films of a fascinating magnetic material, Pr2Ir2O7, in which the magnetic moments are frustrated: No matter how they are arranged, some of the moments are always fighting to change their direction, like two bar magnets with their north poles shoved together. Frustration creates a rich landscape for discovery and manipulation of new magnetic effects and of electronic phenomena linked to magnetism.

This year the Wisconsin MRSEC launched the first Wisconsin MRSEC Excellence in Open Science Prize. The winner was graduate student Bradley Dallin for his work on molecules interacting with water, with potential applications from understanding human blood to protein folding diseases like Alzheimer’s. Bradley shared his results in papers, but also shared all his simulations and tools in an open accessible format for the community, increasing the impact of his work.

The Zhu group developed a facile method to disassemble vdW single crystals layer by layer into monolayers with near-unity yield and with dimensions limited only by bulk crystal sizes (scheme shown on top). The macroscopic monolayers are comparable in quality to microscopic monolayers from conventional Scotch tape exfoliation.

Professor Theanne Schiros spoke to a full house of over 700 as part of a Sustainability Summit focused on the environmental impact of the fashion industry and positive solutions. She is in engaged in sustainable development for economic empowerment of women and artisans in Guinea and Cote d’Ivoire, providing trainings on natural dyes and biofabrication.

We demonstrate a route to high quality interfaces between IV-VI PbSnSe and conventional III-V semiconductors, offering means to host and manipulate electronic states that arise at this interface. We can now clarify the extent to which topological protection from backscattering persist in systems at relevant length scales for logic and interconnects using these novel materials. Heterostructures between IV-VI and III-V materials may enable mid-infrared on-chip environmental and biological sensing.

Hexagonal boron nitride is a suitable host for single-photon emitters and single-spin centers.  Strong single-photon emission has been observed, but the source was not identified.  Based on advanced first-principles simulations, the origins have now been pinpointed: the 2 eV emission has been attributed to boron dangling bonds, and 4 eV emission to carbon-carbon dimers.

NIPS is a non-equilibrium liquid-liquid phase separation phenomenon used to make polymer membranes through solvent-nonsolvent exchange. Newly developed phase-field simulations allow investigation of coupled mass transfer, flow and thermodynamic instability during processing and the corresponding microstructures that result from variations in film composition and thickness. These simulation tools provide critical insight into the nonequilibrium processing of complex fluids to make architectured, resilient solids and soft materials.

After discovering a new magnetic host of skyrmion states, UC Santa Barbara IRG-1 researchers were able to show that chemically alloying the compound FePd1−xPtxMo3N allows for the size of the skyrmion defects to be controlled while still preserving their stability.  Skyrmion states are broadly sought in new materials due to their potential uses in low power memory devices and other spin-based electronics.

Block polymers are a class of versatile self-assembling soft materials that can form exquisite nanostructures for applications including ion transport membranes for batteries and fuel cells, and templates for inorganic oxide catalysts. Using molecular dynamics simulations and transferable force fields, we designed a series of symmetric triblock amphiphiles (or high-χ “block oligomers”) comprising incompatible sugar-based (A) and hydrocarbon (B) blocks that can self-assemble into ordered nanostructures with full domain pitches as small as 1.2 nm.

Atomically-thin sheets of semiconductors have been of immense interest since the Nobel-Prize-winning discovery of graphene or two-dimensional (2D) carbon. Such materials represent the ultimate limit of “scaling” to small sizes, of vital importance in the semiconductor device industry. A particularly exciting recent (2017) finding is that the elemental semiconductor tellurium can be created in 2D sheets, with highly mobile electrons.