Silicon nano-ribbons could lead to better data-storage systems

This was a key finding of a team of scientists led by Paul Snijders of the Department of Energy’s Oak Ridge National Laboratory (ORNL).

According to a statement, the researchers used scanning tunnelling microscopy and spectroscopy to validate first-principle calculations that for years had predicted this outcome.

The discovery, detailed in New Journal of Physics, is said to validate this theory and could move scientists closer towards cost-effectively creating magnetism in non-magnetic materials.

‘While scientists have spent a lot of time studying silicon because it is the workhorse for current information technologies, for the first time we were able to clearly establish that the edges of nano-ribbons feature magnetic silicon atoms,’ said Snijders, a member of ORNL’s Materials Science and Technology Division.

While bulk silicon is non-magnetic, the edges of nano-ribbons of this material are magnetic. Snijders and colleagues at ORNL, Argonne National Laboratory, Wisconsin University and Naval Research Laboratory showed that the electron spins are ordered anti-ferromagnetically.

Configured this way, the up-and-down spin-polarised atoms serve as effective substitutes for conventional zeros and ones common to electron, or charge, current.

‘By exploiting the electron spins arising from intrinsic broken bonds at gold-stabilised silicon surfaces, we were able to replace conventional electronically charged zeros and ones with spins pointing up and down,’ Snijders said.

This discovery provides a new avenue to study low-dimensional magnetism, according to the researchers. Most importantly, such stepped silicon-gold surfaces provide an atomically precise template for single-spin devices at the ultimate limit of high-density data storage and processing.

‘In the quest for smaller and less expensive magnets, electro-motors, electronics and storage devices, creating magnetism in otherwise non-magnetic materials could have far-reaching implications,’ Snijders added.

The research was funded by the Department of Energy’s Office of Science, the National Science Foundation and the Office of Naval Research. The paper is available here.