Washington, December 22
Scientists at the US Department of Energy’s (DOE) Argonne National Laboratory report they can precisely rotate a single molecule that could lead to new technologies for microelectronics, quantum computing and more, according to a study.
The key ingredient is a single atom of europium, a rare earth element. It rests at the center of a complex of different atoms and gives the molecule many potential applications, he said.
“Our primary mission is to understand at the atomic level the properties of rare earths, which are critical materials for US industry,” said Saw Wai Hla, a physicist at the Center for Nanoscale Materials (CNM), a Bureau user facility. of Science from the DOE. at Argonne, and professor of physics at Ohio University.
The term “rare earth” is misleading. Rare earth elements aren’t exactly rare, but they are critical materials used in many electronic devices, including cell phones, computer hard drives, solar panels, and flat panel monitors.
“We can rotate this europium complex 60 or 120 degrees to the right or to the left,” Hla said. “The ability to control the movement of a rare earth complex like this could affect a wide spectrum of technologies.”
According to the study, the ability to rotate this europium molecule on demand could expand its applications to next-generation microelectronics that run on relatively low power, quantum computers, and more.
Rare earths easily combine with other elements in the earth’s crust. Therefore, it is difficult and expensive to produce pure rare earths for devices. They are also expensive to collect from waste that contains rare earths. The team’s europium complex would reduce the amount of rare earths needed for a particular device and would be much less expensive to manufacture in mass quantities, according to the study.
The key components of the complex are a single positively charged europium atom and two small negatively charged molecules. The europium atom is in the center of the complex, while one of the small molecules is on the side and the other on the bottom, according to the study.
According to the study, because opposites attract, these positive and negative charges hold these components together without the need for a chemical bond. And the little molecule at the bottom anchors the complex to gold foil. This sheet acts as a table to hold the entire complex in one place, in the same way that a solid, flat surface is needed to spin a bottle.
“Normally, if you put a complex like ours with positive and negative charges on a sheet of metal, the charges dissipate,” Hla said. “So, we got excited when that didn’t happen here. Our calculations indicated that the atoms in the complex surrounding the europium atom act as an insulator that prevents charges from dissipating into the gold foil.”
The two negatively charged molecules in the complex work together to act as a control unit. To cause the rotation, the team applied electrical energy to a specific point on the complex through the tip of an instrument called a scanning tunneling microscope. This probe not only monitors the rotation but can also image the complex for study, the study said.
At a temperature of 100 Kelvin (minus 208 Fahrenheit), the team’s complex rotates constantly. That rotation stops when they decrease the temperature to an ultracold 5 K. Applying electrical power starts the desired rotation of 60 or 120 degrees, clockwise or counterclockwise, depending on where the electric field is directed.
“Developing, manufacturing and testing this nanoscale complex would not have been possible without the one-of-a-kind instruments at CNM,” Hla noted.