Scientists are exploring materials just one atom thick, called 2D materials, to create the electronics of the future.

These materials have unique properties that could make devices more efficient.

When two of these sheets are stacked at specific angles, new behaviors, like superconductivity, can emerge.

However, researchers recently discovered surprising results that challenge previous predictions.

A team led by materials scientist Antonija Grubišić-Čabo from the University of Groningen investigated a 2D material called tungsten disulfide.

Working with colleagues from Poland, Germany, France, and Italy, they looked at what happens when two sheets of this material—known as a bilayer—are twisted at an angle of 4.4 degrees.

According to theories, electrons in the bilayer should work together in a collective way, creating exciting effects.

But when the researchers conducted experiments, they didn’t observe this collective behavior. Giovanna Feraco, the study’s first author, explained that the interactions between atoms in the bilayer weren’t behaving as expected.

Typically, twisting the sheets at specific angles allows the atoms to interact closely, leading to unique electronic properties.

Instead, the team found that the material partially “relaxed” into regions where the sheets were untwisted. In simple terms, the bilayer settled into a state that required less energy, forming large areas where the sheets weren’t twisted anymore.

This change disrupted the collective electron behavior predicted by theories.

“Our study shows that the twisted bilayer doesn’t stay perfectly twisted,” Feraco said. “It tends to form areas with different properties, which changes the overall behavior of the material.”

This discovery is important because it shows how these tiny materials behave differently in real life compared to theoretical models. By studying how the sheets form regions with varying properties, scientists can better predict and control the behavior of 2D materials. This could lead to new advances in electronics.

The findings, published in the journal Physical Review Materials, highlight the complexity of these materials and how they might be used in future technologies. Understanding the way 2D materials like tungsten disulfide behave will help researchers develop new kinds of electronics, from faster computers to more efficient energy devices.

“We’re learning how to manipulate these materials to unlock their full potential,” said Grubišić-Čabo. This research is a step toward harnessing the power of 2D materials for tomorrow’s technology.

Source: University of Groningen.