International scholar research may open doors to “spintronics”

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Since long before Newton and his fabled apple, physicists have devoted their careers to observing the properties of the physical universe. Matter has its own behaviour, and physicists have discovered and put to use many of the properties of matter in industrial applications. For example, the discovery of quantum physics gave way to an understanding of semiconductors, which today can be found in just about every electronic device we use.

Semiconductors were the product of what some scientists call the “Observation Age." Dr. Giancarlo Panaccione, Peter Wall Institute International Visiting Research Scholar, says we are now in the “Control Age”– and his research is helping to usher it in.

“This means controlling the characteristics or functionalities of specific samples in terms of solids, or gas, or molecules," he explains from his laboratory in Trieste, Italy, “and try to use them in a way that is controlled by ourselves."

“This– one should say this in a modest way– is simply the way in which now, technology and science is able to manipulate atoms and solids… materials science is now learning how to make a metal ‘less’ metallic, or how to make a semiconductor ‘more’ conductive.”

This ultra-high-vacuum photoelectron spectrometer, developed in Dr. Andrea Damascelli’s Quantum Materials Laboratory at UBC, is used to measure the velocity and direction of motion of the electrons in novel quantum systems at cryogenic temperatures, with unprecedented precision.

While the manipulation of semiconductors is one promising application for new technologies, Dr. Panaccione’s research focuses on topological insulators, a recently discovered class of material in which the interior acts as an insulator while just the surface conducts electricity. He compares the properties of these insulators to a gold-coated ceramic disc. Since gold is a conductor and ceramic is an insulator, electricity would flow around the surface of the dish but not through it since the object is made of two different materials.

“The peculiarity of topological insulators is that the material is the same, but the properties of the surface are completely different to the properties of the volume," he explains.

Just as semiconductors opened the door to televisions and cell phones, topological insulators, only first theorized a few years ago, could be key to the age of “spintronics,” which is based on the spin of electrons to carry information and quantum computing.

Dr. Panaccione’s work while in residence at the Peter Wall Institute enabled him to make use of the specialized equipment at the University of British Columbia (UBC) that is necessary for his research. The magnetic and electronic properties of matter change as the temperature approaches the extreme low of 0 degrees kelvin, so the Italian physicist needed someplace quite cold to conduct his experiments.

“They have an experimental setup that is almost unique in the world," he says, “because it is a setup to study the properties of materials at very, very low temperatures… close to absolute zero.”

Over three visits, Dr. Panaccione made the most of the collaborative research spirit of the Peter Wall Institute fellowship, delivering a public lecture as well as working closely with Dr. Andrea Damascelli and Dr. George Sawatsky, researchers at UBC’s Quantum Material group of the Advanced Materials and Process Engineering Laboratory (AMPEL) and in the Department of Physics and Astronomy. Together, they combined knowledge of topological insulators and access to equipment for ultra-low temperature research to better understand how to manipulate solids and surfaces.

“So many groups are specialized in a specific subject of activity,” he says. “In our case, the two specializations that we had, they were good starting points to understand the properties of these materials– and the Peter Wall Institute was the node where it was possible to join together these ideas and exchange these ideas with students and post-docs and staff.”