News from the NNI Community - Research Advances Funded by Agencies Participating in the NNI

A team of researchers co-led by the Department of Energy's Lawrence Berkeley National Laboratory has observed long-lived plasmons in a new class of conducting transition metal dichalcogenides (TMDs) called quasi 2D crystals. The researchers developed sophisticated new algorithms to compute the material's electronic properties, including plasmon oscillations with long wavelengths. To the researchers' surprise, the results from their calculations revealed that plasmons in quasi 2D crystals are more stable – for as long as approximately 2 trillionths of a second – than previously thought.

A team of researchers co-led by the Department of Energy's Lawrence Berkeley National Laboratory has observed long-lived plasmons in a new class of conducting transition metal dichalcogenides (TMDs) called quasi 2D crystals. The researchers developed sophisticated new algorithms to compute the material's electronic properties, including plasmon oscillations with long wavelengths. To the researchers' surprise, the results from their calculations revealed that plasmons in quasi 2D crystals are more stable – for as long as approximately 2 trillionths of a second – than previously thought.

Scientists at the University of Massachusetts Amherst have developed bioelectronic ammonia gas sensors that are among the most sensitive ever made. The sensors use electric-charge-conducting protein nanowires derived from the bacterium Geobacter, which grows hair-like protein filaments that work as nanoscale "wires" to transfer charges for their nourishment and to communicate with other bacteria.

Scientists at the University of Massachusetts Amherst have developed bioelectronic ammonia gas sensors that are among the most sensitive ever made. The sensors use electric-charge-conducting protein nanowires derived from the bacterium Geobacter, which grows hair-like protein filaments that work as nanoscale "wires" to transfer charges for their nourishment and to communicate with other bacteria.

Plastics are a popular 3-D printing material, but printed parts are mechanically weak—a flaw caused by the imperfect bonding between the individual printed layers that make up the 3-D part. Now, researchers at Texas A&M University, in collaboration with scientists in the company Essentium, Inc. have developed a technology that overcomes this flaw. By integrating plasma science and carbon nanotube technology into standard 3-D printing, the researchers welded adjacent printed layers more effectively, increasing the overall reliability of the final part.

Plastics are a popular 3-D printing material, but printed parts are mechanically weak—a flaw caused by the imperfect bonding between the individual printed layers that make up the 3-D part. Now, researchers at Texas A&M University, in collaboration with scientists in the company Essentium, Inc. have developed a technology that overcomes this flaw. By integrating plasma science and carbon nanotube technology into standard 3-D printing, the researchers welded adjacent printed layers more effectively, increasing the overall reliability of the final part.

In 2018, MIT scientists discovered that when two sheets of graphene are stacked together at a slightly offset "magic" angle, the new "twisted" graphene structure can become either an insulator or a superconductor. Now, the MIT scientists report that they and others have imaged and mapped an entire twisted graphene structure for the first time at a resaolution fine enough that they are able to see slight variations in the local twist angle across the entire structure. The scientists also reported creating a new twisted graphene structure with not two, but four layers of graphene. They observed that the new four-layer magic-angle structure is more sensitive to certain electric and magnetic fields compared to its two-layer predecessor. 

In 2018, MIT scientists discovered that when two sheets of graphene are stacked together at a slightly offset "magic" angle, the new "twisted" graphene structure can become either an insulator or a superconductor. Now, the MIT scientists report that they and others have imaged and mapped an entire twisted graphene structure for the first time at a resolution fine enough that they are able to see slight variations in the local twist angle across the entire structure. The scientists also reported creating a new twisted graphene structure with not two, but four layers of graphene. They observed that the new four-layer magic-angle structure is more sensitive to certain electric and magnetic fields compared to its two-layer predecessor. 

Researchers at Rice University have found evidence of piezoelectricity in lab-grown, two-dimensional flakes of molybdenum dioxide that are less than 10 nanometers thick. Piezoelectricity is a property of materials that respond to stress by generating an electric voltage across their surfaces or generate mechanical strain in response to an applied electric field. The researchers found that the surprise electrical properties are due to electrons trapped in defects throughout the material.

Researchers at Rice University have found evidence of piezoelectricity in lab-grown, two-dimensional flakes of molybdenum dioxide that are less than 10 nanometers thick. Piezoelectricity is a property of materials that respond to stress by generating an electric voltage across their surfaces or generate mechanical strain in response to an applied electric field. The researchers found that the surprise electrical properties are due to electrons trapped in defects throughout the material.