Fourth-year physics doctoral candidate Alessandro Mazza (left) works on an ultra-high vacuum called X3B2 with physics graduate student Alexander Daykin in Prof. Paul Miceli's lab.
“For more than 50 years, Moore's Law has reigned supreme. The observation that the number of transistors on a computer chip doubles roughly every two years has set the pace for our modern digital revolution—making smartphones, personal computers and current supercomputers possible. But Moore's Law is slowing. And even if it wasn't, some of the big problems that scientists need to tackle might be beyond the reach of conventional computers.” – (https://phys.org/news/2017-09-quantum-tackle-fundamental-science-problem...)
Alessandro Mazza, a fourth-year doctoral candidate in physics, might help make quantum computing a reality. Mazza recently received a Department of Energy (DOE) research award that will allow him to carry out part of his doctoral research at the DOE’s Oak Ridge National Laboratory in eastern Tennessee. The research award will allow Mazza to continue the work he began with physics Professor Paul Miceli when Mazza arrived at MU.
“When I first came here, I wanted to work for Paul, but when I got this IGERT (Integrative Graduate Education and Research Traineeship) grant shortly after I arrived, Paul and I had to come up with a project that utilized neutron scattering,” Mazza says. “We decided to play to the strengths of neutrons and look at a non-conventional type of magnetism in graphene.”
The IGERT grant, entitled “Neutron Scattering for the Science and Engineering of the 21st Century”, is funded by the National Science Foundation. The grant’s objective is to leverage the neutron scattering instruments at the Missouri University Research Reactor (MURR) for training graduate students – the capabilities arising from the suite of neutron scattering instruments at MURR are unique for a university campus.
Graphene is a single layer of graphite that has a number of novel properties that interest physicists.
“What is interesting about our project is we are taking a material that’s only carbon, and we’re making it magnetic,” Mazza says. “Usually with magnetism you think of iron or cobalt—these heavy metals that have a type of magnetism that’s pretty well understood. Other researchers have explored carbon magnetism theoretically or produced it in the lab, but our study attempts to say why it’s magnetic. Our goal is to be the first to explain the mechanism of this magnetism.”
Mazza leaves for his new assignment at Oak Ridge in early October and will spend two years at the national lab continuing his research into graphene magnetism as well as creating other novel materials that exhibit this type of magnetism. Mazza looks forward to being able to use the facility’s neutron-scattering device for his specific technique: polarized neutron reflectivity.
Neutron scattering is routinely used to understand material properties on the atomic scale. He compares his technique to the more common x-ray scattering.
“In x-ray scattering, you shoot a beam of x-ray wavelength light at your material, and it scatters off the electrons surrounding your atom, revealing the physical properties of materials and thin films,” Mazza says. “Neutron scattering really probes the structure of magnetism—where it lies in your sample, how it exists in your sample. Polarized neutron reflectivity, a technique using the magnetic moment of the neutron, allows the study of magnetism in very thin films like graphene. The novelty of the process is that it gives structural information simultaneously with magnetic information by comparing the spin up/spin down scattering from a polarized neutron beam.”
It’s this spin up/spin down feature that lies at the heart of a spintronic device—a precursor to quantum computing. Mazza says a computer basically works on an on–off switch—a zero and a one—for a simple logic operation. The spintronic device, rather than using a physical on–off switch, uses the spin up or spin down of electrons to perform logic functions.
“So a magnetic sheet of graphene could store the zeroes and ones in a computer with electrons rather than with switches, and that has a number of unique advantages in quantum computing,” Mazza says. “Another big upside is it would generate a lot less heat than a typical computer, so you could make logic devices that are much smaller and energy efficient than what’s available on your typical silicon chip.”