Researchers from EPFL‘s Theory and Simulation of Materials Laboratory (THEOS) and from NCCR-MARVEL for Computational Design and Discovery of Novel Materials have been recognizing many more promising 2D materials.
2D materials, which consist of a few layers of atoms, may well be the future of nanotechnology. They offer potential new applications and could be utilized in small, higher-performance and more energy-efficient devices.
2D materials were first discovered almost 15 years ago, but only a few dozen of them have been synthesized so far.
The first 2D material to be isolated was graphene, in 2004, earning the researchers who brought it a Nobel Prize in 2010. This marked the start of a whole new era in electronics, as graphene is light, transparent and resilient and, above all, a good conductor of electricity. It paved the way to new applications in numerous fields such as photovoltaics and optoelectronics.
Nicolas Mounet, a researcher in the THEOS lab and lead author of the study explained, “To find other materials with similar properties, we focused on the feasibility of exfoliation.”
“But instead of placing adhesive strips on graphite to see if the layers peeled off like the Nobel Prize winners did, we used a digital method.”
Further, the researchers developed an algorithm to review and carefully analyze the structure of more than 100,000 3D materials recorded in external databases. From this, they created a database of around 5,600 potential 2D materials, including more than 1,000 with particularly promising properties. In other words, they’ve created a treasure trove for nanotechnology experts.
Later to build their database, the researchers used a step-by-step process of elimination. First, they identified all of the materials that are made up of separate layers.
Marco Gibertini, a researcher at THEOS said, “We then studied the chemistry of these materials in greater detail and calculated the energy that would be needed to separate the layers, focusing primarily on materials where interactions between atoms of different layers are weak, something is known as Van der Waals bonding.”
Of the 5,600 materials initially identified, the researchers singled out 1,800 structures that could potentially be exfoliated, including 1,036 that looked especially easy to exfoliate. This represents a considerable increase in the number of possible 2D materials known today. They then selected the 258 most promising materials, categorizing them according to their magnetic, electronic, mechanical, thermal and topological properties.
Nicola Marzari, the director of NCCR Marvel and a professor at THEOS said, “Our study demonstrates that digital techniques can really boost discoveries of new materials.”
“In the past, chemists had to start from scratch and just keep trying different things, which required hours of lab work and a certain amount of luck. With our approach, we can avoid this long, frustrating process because we have a tool that can single out the materials that are worth studying further, allowing us to conduct more focused research.”
It is also possible to reproduce the researchers’ calculations thanks to their software AiiDA, which describes the calculation process for each material discovered in the form of workflows and stores the full provenance of each stage of the calculation.
Giovanni Pizzi, a senior researcher at THEOS and co-author of the study explained, “Without AiiDA, it would have been very difficult to combine and process different types of data.”
“Our workflows are available to the public, so anyone in the world can reproduce our calculations and apply them to any material to find out if it can be exfoliated.”
The work is recently published in the journal Nature Nanotechnology, and even got a mention on the cover page.