Researchers have expanded their understanding of van der Waals crystals to include magnetic materials, offering one of the most ambitious platforms to investigate and manipulate phases of matter at the nanoscale.
Scientists have long wanted to learn more about 2D magnetism in an attempt to unleash new states of matter and utility in nano-devices. There have been predictions in the past that the magnetic moments of electrons would no longer be able to align in perfectly clean systems, which could unveil several new states of mater and enable novel forms of quantum computing.
“The point of our perspective is that there has been a huge emphasis on devices and trying to pursue these 2D materials to make these new devices, which is extremely promising,” Boston College Associate Professor of Physics Kenneth Burch, a first author of the study, said in a statement. “But what we point out is magnetic 2D atomic crystals can also realize the dream of engineering these new phases—superconducting, or magnetic or topological phases of matter, that is really the most exciting part.
“These new phases would have applications in various forms of computing, whether in spintronics, producing high temperature superconductors, magnetic and optical sensors and in topological quantum computing,” he added.
A key hurdle remains the successful fabrication of perfectly clean systems and their incorporation with other materials. Van der Waals crystals—which are held together by friction—has been used to isolate single-atom-thick layers that lead to numerous new physical effects and applications.
Graphene, a crystal constructed in uniform, atom-thick layers, is the most often cited example of a van der Waals crystal. A procedure as simple as applying a piece of scotch tape to the crystal can remove a single layer to provide a thin, uniform section that serves as a platform to develop novel materials with a range of physical properties able to be manipulated.
“What’s amazing about these 2D materials is they’re so flexible,” Burch said. “Because they are so flexible, they give you this huge array of possibilities.
“You can make combinations you could not dream of before…A student working with tape puts them together. That adds up to this exciting opportunity people dreamed of for a long time, to be able to engineer these new phases of matter,” he added.
Within a single layer, the researchers focused on spin, where the charge of an electron can be used to send either off or on signals, resulting in multiple points of control and measurement, an exponential expansion of the potential to signal, store or transmit information in the smallest spaces.
“One of the big efforts now is to try to switch the way we do computations,” Burch said. “Now we record whether the charge of the electron is there or it isn’t.
“Since every electron has a magnetic moment, you can potentially store information using the relative directions of those moments, which is more like a compass with multiple points,” he added. “You don’t just get a one and a zero, you get all the values in between.”
Moving forward, the researchers would like to discover new materials with specific functionality, including materials isotropic or complex magnetic interactions that could play a role in the development of new superconductors.
The new materials could also result in a deeper understanding of the fundamental issues of condensed matter physics. The materials will also be tested for the potential to become unique devices capable of delivering novel applications.
The materials also could lead to new exotic states like quantum spin liquids, skyrmions and new iterations of superconductivity because they possess quantum and topological phases.
An international team that included scientists from Boston College, the University of Tennessee, and Seoul National University conducted the study.
The study was published in Nature.
