For the first time, scientists see the properties of these materials (Microscopic imaging may lead to new ways to control excitons for quantum computing) locked in thin materials, opening new ways to control excitons for quantum and optoelectronic applications.
Excitons attract attention as possible quantum bits (qubits) in the computer of tomorrow and are central to optoelectronics and aggressive systems. However, these neutral charges, which exist in semiconductors and other materials, are difficult to control and control. Now, for the first time, researchers have created and directly observed excitons trapped inside a tiny package of three important materials. The work confirms the predictions and opens new avenues for controlling excitons in structured materials.
“The idea that you can map excitons to specific lattice (Microscopic imaging may lead to new ways to control excitons for quantum computing) sites by measuring these 2D objects is exciting because it has a variety of applications, from creating optoelectronic devices to materials for quantum information science. ,” said Archana Raja, director of the project. . and a geneticist at the Lawrence Berkeley National Laboratory (Berkeley Lab), whose team led the creation of tools and identification through visual observation.
The team produced the device by stacking a layer of tungsten disulfide (WS2) and tungsten diselenide (WSe2). The slight overlap in the spacing of the atoms in the two elements results in a moiré superlattice, a larger pattern in time that results from the combination of two smaller patterns that have similar but not identical properties. Using state-of-the-art electron microscopy tools, the researchers collected structural and spectroscopic data on the devices, combining information from hundreds of measurements to determine the likely location of the exciton.
“We did this experiment with the highest power of our most advanced microscope,” said Peter Ercius, who led the imaging project at the Molecular Foundry’s National Center for Electron Microscopy. “We were pushing the limits of everything we could do, from and developing examples and empirical research and theory.”
Theoretical calculations, led by Steven Louie, Berkeley Lab Principal Investigator and Professor of Physics at UC Berkeley, revealed that large atomic reconstructions take place in stacked materials, which modulate the electronic structure to form a periodic system of “traps” “. where excitons exist. The discovery of this direct relationship between the structural changes and the exciton field overturns the previous understanding of these processes and establishes a new approach to the design of optoelectronic devices.
The team’s findings were detailed in an article published in the journal Science with postdoctoral fellows Sandhya Susarla (now a professor at Arizona State University) and Mit H. Naik as the co-lead author. Next, the team will explore ways to replicate the moiré network in search and make the event robust to hardware issues.
