(Funded by the U.S. National Science Foundation and the U.S. Department of Energy)
When materials are created on a nanometer scale, even the thermal energy present at room temperature can cause structural ripples. How these ripples affect the mechanical properties of these thin materials can limit their use in electronics and other key systems. Now, using a semiconductor manufacturing process, researchers from Binghamton University, Harvard University, Princeton University, Penn State, and the U.S. Department of Energy’s Argonne National Laboratory have created alumina structures that are 28 nanometers thick on a silicon wafer with thermal-like static ripples, and then tested these ripples with lasers to measure their behavior. The results match with theories proposed about such structural ripples.

(Funded by the U.S. Department of Energy)
An international team led by Rutgers University-New Brunswick researchers has merged two lab-synthesized two-dimensional materials into a synthetic quantum structure once thought impossible to exist and produced an exotic structure expected to provide insights that could lead to new materials at the core of quantum computing. One slice of the quantum structure is made of dysprosium titanate, an inorganic compound used in nuclear reactors, while the other is composed of pyrochlore iridate, a new magnetic semimetal. The specific electronic and magnetic properties of the material developed by the researchers can help in creating very unusual yet stable quantum states, which are essential for quantum computing.

(Funded by the U.S. Department of Energy and the U.S. National Science Foundation)
The shape of nanoparticles depends on the choice of solvent and temperature during their growth. But the tiny seed particles that form first and that guide the formation of final nanoparticle shapes are too small to measure accurately. With the help of a supercomputer, Penn State researchers have developed computer simulations to model seed particles with 100 to 200 atoms. They found that the shapes of the tiny particles depend on the solvent composition and temperature in unexpected ways. Surprisingly, in some cases the shape of the seed particle changes dramatically when only a single atom is added or removed.

(Funded by the U.S. Department of Energy)
Stacking single layers of sub-nanometer-thick semiconductor materials, known as transition metal dichalcogenides, can generate a moiré potential – a “seascape” of potential energy with regularly repeating peaks and valleys. These peaks and valleys were previously thought to be stationary, but now, researchers from the Molecular Foundry, a user facility at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory, and the University of California, Berkeley, along with international collaborators, have shown that the moiré potentials that emerge when transition metal dichalcogenides are stacked are constantly moving, even at low temperatures. Their discovery contributes to foundational knowledge in materials science and holds promise for advancing the stability of quantum technologies, because controlling moiré potentials could help mitigate decoherence in qubits and sensors. (Decoherence occurs when interference causes the quantum state and its information to be lost.)

(Funded by the U.S. National Science Foundation and the U.S. Department of Energy)
Scientists from the U.S. Department of Energy’s (DOE) Argonne National Laboratory (ANL) and SLAC National Accelerator Laboratory; the University of Chicago; the University of Vermont; Middlebury College; Brown University; Stanford University; and Northwestern University have observed that when semiconductor nanocrystals called quantum dots were exposed to short bursts of light, the symmetry of the crystal structure changed from a disordered state to a more organized one. The return of symmetry directly affected the electronic properties of the quantum dots by causing a decrease in the bandgap energy, which is the difference in energy that electrons need to jump from one state to another within a semiconductor material. This change can influence how well quantum dots conduct electricity and respond to electric fields. Part of this work was conducted at the Center for Nanoscale Materials, a DOE Office of Science user facility at ANL.