A team of researchers at the University of Texas in Arlington has discovered a way to cool electrons to -378.4°F (-228°C) without external means and at room temperature — an advancement that could enable electronic devices to function with very little energy, say the researchers.

The process involves passing electrons through a quantum well to cool them and keep them from heating, and the breakthrough comes in the researchers' ability to cool the electrons at room temperature. “We are the first to effectively cool electrons at room temperature," says Seong Jin Koh, an associate professor in the Materials Science & Engineering department at University of Texas in Arlington. Koh, who led the research team, added, "Researchers have done electron cooling before, but only when the entire device is immersed into an extremely cold cooling bath. Obtaining cold electrons at room temperature has enormous technical benefits. For example, the requirement of using liquid helium or liquid nitrogen for cooling electrons in various electron systems can be lifted."

Koh notes that electrons are thermally excited even at room temperature — it is a natural phenomenon. The researchers posited that if that electron excitation could be suppressed, then the temperature of those electrons could be effectively lowered without external cooling, Koh said.

The team used a nanoscale structure — consisting of a sequential array of a source electrode, a quantum well, a tunneling barrier, a quantum dot, another tunneling barrier, and a drain electrode — to suppress electron excitation and to make electrons cold. The cold electrons promise a new type of transistor that can operate at extremely low-energy consumption. “Implementing our findings to fabricating energy-efficient transistors is currently under way,” Koh added.

The research was published in “Energy-filtered cold electron transport at room temperature,” in Nature Communications.