Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have unveiled a new technique that could help advance the development of quantum technology. Their innovation provides an unprecedented look at how quantum materials behave at interfaces. “This technique allows us to study surface phonons — the collective vibrations of atoms at a material’s surface or interface between materials,” said Zhaodong Chu, one of the scientists involved in this study. ​“Our findings reveal striking differences between surface phonons and those in the bulk material, opening new avenues for research and applications.” Some of the research activities were performed at Argonne’s Center for Nanoscale Materials, a DOE Office of Science user facility.

(Funded by the U.S. Department of Energy)
Researchers from Rice University; the Massachusetts Institute of Technology; Carnegie Mellon University; the National University of Singapore; Southern University of Science and Technology in Shenzhen, China; and Osaka University in Japan have found a two-dimensional (2D) carbon material that is tougher than graphene and resists cracking. Carbon-derived materials, such as graphene, are among the strongest on Earth, but once established, cracks propagate rapidly through them, making them prone to sudden fracture. The new carbon material, called a monolayer amorphous carbon, is both strong and tough. Like graphene, this material is also a 2D material, but unlike graphene, in which atoms are arranged in an ordered lattice, this material incorporates both crystalline and amorphous regions. “This unique design prevents cracks from propagating easily, allowing the material to absorb more energy before breaking,” said Bongki Shin, one of the researchers involved in this study.

(Funded by the U.S. Department of Energy)
Scientists from the U.S. Department of Energy’s (DOE) Argonne National Laboratory, SLAC National Accelerator Laboratory, and Lawrence Berkeley National Laboratory; the University of California, Berkeley; Pennsylvania State University; Stanford University; Rice University; the Indian Institute of Science in Bangalore, India; the Japan Synchrotron Radiation Research Institute in Sayo, Japan; RIKEN SPring-8 Center in Sayo, Japan; and the University of Tokyo in Japan are investigating a material with a highly unusual structure – one that changes dramatically when exposed to an ultrafast pulse of light from a laser. At the Center for Nanoscale Materials, a DOE Office of Science user facility at Argonne, the scientists used a technique called transient absorption spectroscopy to detect photocarrier activity within the material. This approach helped them determine how much charge gets released and how quickly the charge decays.

(Funded by the U.S. Department of Energy)
Most optical sensors record data from light and then transmit all of the raw data to a computer for processing. This typically consumes more energy than necessary, because in most applications, only a small amount of information relative to the raw data is needed. So, scientists from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and Sandia National Laboratories; the University of California, Berkeley; the University of California, Davis; and the University of Texas at Arlington are developing a less power-hungry approach, in which some data processing is conducted in the sensor itself, before the data is sent to a computer or processed by edge computing devices. The new sensor, called a “nanoscale hybrid,” stitches together nanostructures, such as nanotubes and nanowires. It is highly sensitive in part because the sensor’s nanoscale components are smaller than the wavelength of light.

(Funded by the U.S. Department of Defense and the U.S. Department of Energy)
Researchers from Rice University, the University of California Berkeley, the University of Pennsylvania, and the Massachusetts Institute of Technology have shed light on how the extreme miniaturization of thin films affects the behavior of relaxor ferroelectrics — materials with noteworthy energy-conversion properties used in sensors, actuators, and nanoelectronics. The findings reveal that as the films shrink to dimensions comparable to internal polarization structures within the films, their fundamental properties can shift in unexpected ways. More specifically, when the films are shrunk down to a precise range of 25–30 nanometers, their ability to maintain their structure and functionality under varying conditions is significantly enhanced.