Chinese scientists have achieved a milestone in materials science by successfully compressing metals into ultra-thin sheets, measuring just a few atoms thick. This breakthrough was inspired by ancient copper-forging techniques.
A team from the Institute of Physics at the Chinese Academy of Sciences in Beijing has developed a novel method to create ultra-thin sheets of metals like bismuth, gallium, indium, tin, and lead. Some of these sheets reach an astonishing thickness of just one atom, making them hundreds of thousands of times thinner than human hair.
Published in the journal Nature, the study highlights the exceptional electrical conductivity and unique properties of these atomically thin metals, particularly bismuth. According to Javier Sanchez-Yamagishi, a 2D materials specialist at the University of California, Irvine, while other teams have previously created thin metals, this research stands out due to its ability to produce “large-scale, truly 2D metals.”
“The stability and large sizes of these materials open up many possibilities for integrating them with other materials and for making new electrical or photonic devices,” Sanchez-Yamagishi wrote in a review article in Nature.
Scientists have long known that two-dimensional (2D) materials behave drastically differently from their three-dimensional (3D) counterparts, even when they share the same chemical composition. For example, graphene, a single-atom-thick sheet of carbon, is significantly stronger and more conductive than the graphite found in pencils. However, peeling graphene from crystalline carbon is relatively simple due to its natural layered structure, resembling stacked sheets of lasagna.
In contrast, metals have tightly packed atomic structures similar to compressed biscuits, making it extremely challenging to separate them into ultra-thin sheets. To overcome this, nano device specialist Zhang Guangyu and his team devised a unique approach using sapphire slabs coated with molybdenum disulfide. This material stabilizes the ultra-thin metal, preventing oxidation and allowing for successful extraction.
By heating a tiny droplet of metal on one slab and pressing it with another, the team was able to spread the metal into an ultra-thin sheet as it cooled. Using this technique, they successfully created sheets of five different metals just a few atoms thick, measuring a few hundred micrometers wide—an impressive feat for such an incredibly thin material. The researchers believe this method can be extended to other metals with low melting points.
According to Zhang, 2D metals have vast application potential, ranging from miniaturized electronic devices to quantum information processing, data storage, and ultra-sensitive detection.
“For instance, they could serve as interconnects in chips or even as core materials for chip fabrication,” Zhang explained to Chinese state broadcaster CCTV.
However, Stanford University electrical engineer Eric Pop cautioned that integrating ultra-thin metal sheets into commercial electronics still poses significant challenges. One of the biggest hurdles is ensuring their stability at the high temperatures required for chip manufacturing. Until researchers can confirm their durability under such conditions, widespread adoption remains uncertain.
