A University of Minnesota team has created a new material that can improve computer processing and memory efficiency.
This cross-sectional transmission electron microscope image shows a sample used for the charge-to-spin conversion experiment. (Source: Wang Group, University of Minnesota)
"We used a quantum material that has attracted a lot of attention by the semiconductor industry in the past few years, but created it in unique way that resulted in a material with new physical and spin-electronic properties that could greatly improve computing and memory efficiency," said lead researcher Jian-Ping Wang, a University of Minnesota Distinguished McKnight Professor and Robert F. Hartmann Chair in electrical engineering.
The new material is part of a class of materials called “topological insulators.” Topological insulators are typically created with a crystal growing process of Molecular Beam Epitaxy, or crystals grown on films. Neither of these methods can be scaled up for larger production.
The team used a different method to create the quantum material, called “sputtering.” The sputtering method is a thin-film deposition technique that is driven by momentum exchange between ions and atoms. This was the first time that this method has been used to create an insulator material and the method can be scaled up for larger production.
The grains in the thin layer created new physical properties that are key to improving computer processing and memory. The resulted computer processing is 18 times better than current efforts.
"As the size of the grains decreased, we experienced what we call 'quantum confinement' in which the electrons in the material act differently giving us more control over the electron behavior," said study co-author Tony Low, a University of Minnesota assistant professor of electrical and computer engineering.
"Using our advanced aberration-corrected scanning TEM we managed to identify those nano-sized grains and their interfaces in the film," said Andre Mkhoyan, a University of Minnesota associate professor of chemical engineering and materials science and electron microscopy expert.
"Using the sputtering process to fabricate a quantum material like a bismuth-selenide-based topological insulator is against the intuitive instincts of all researchers in the field and actually is not supported by any existing theory," Wang said. "Four years ago, with a strong support from Semiconductor Research Corporation and the Defense Advanced Research Projects Agency, we started with a big idea to search for a practical pathway to grow and apply the topological insulator material for future computing and memory devices. Our surprising experimental discovery led to a new theory for topological insulator materials."
The paper on the new technology was published in Nature Materials
