In everyday materials like glass, atoms are arranged in a random, disordered way—much like grains of sand on a beach—and creating this “amorphous” state typically takes a lot of energy. The most common approach is to heat the material until it liquefies and then cool it rapidly to prevent the atoms from forming an ordered structure, like in a crystal.
Now, researchers led by Ritesh Agarwal, materials science and engineering professor at the School of Engineering and Applied Science, and his collaborators have developed a breakthrough method for creating an amorphous state in indium selenide with much less energy—up to a billion times less. This discovery, published in Nature, could open new possibilities for an innovative data storage technology called phase-change memory, which could revolutionize everything from smartphones to computers.
In phase-change memory, information is stored by switching the material between amorphous and crystalline states, functioning like an on/off switch. However, large-scale commercialization has been limited by the high power needed to create these transformations.
For more than a decade, Agarwal’s group has studied alternatives to the melt-quench process, which involves heating a material until it liquifies, following their 2012 discovery that electrical pulses can amorphize alloys of germanium, antimony, and tellurium without needing to melt the material.
“We learned that multiple properties of [indium selenide]— the 2D aspect, the ferroelectricity and the piezoelectricity—all come together to design this ultra-low energy pathway for amorphization through shocks,” says Agarwal.
The collaborative effort to understand the process has created fertile ground for future discoveries. “This opens up a new field on the structural transformations that can happen in a material when all these properties come together. The potential of these findings for designing low-power memory devices are tremendous,” says Agarwal.
This story is by Ian Scheffler. Read more at Penn Engineering Today.
