Researchers at North Carolina State University (NCSU) have reported a new distinct form of silicon called Q-silicon which, among other interesting properties, is ferromagnetic at room temperature. The team's recent findings could lead to advances in quantum computing, including the creation of a spin qubit quantum computer that is based on controlling the spin of an electron.
“The discovery of Q-silicon having robust room temperature ferromagnetism will open a new frontier in atomic-scale, spin-based devices and functional integration with nanoelectronics,” said Jay Narayan, the John C. Fan Family Distinguished Chair in Materials Science and corresponding author of the paper describing the work.
Ferromagnetism in materials outside of transition metals and rare earths has fascinated scientists for a long time, because spin-polarized electrons can be used to process and store information with atomic resolution. However, materials with even numbers of electrons, such as carbon and silicon, without unpaired spins were not considered seriously in terms of bulk ferromagnetism. The dangling bonds in bulk carbon and silicon materials usually reconstruct and eliminate sources of unpaired electrons.
The researchers showed that laser melting and quenching silicon can result in the formation of Q-silicon. The entire process is completed in less than a fraction of a microsecond, or millionth of a second. Narayan pioneered the use of lasers to create new materials with novel properties in work spanning more than four decades.
Besides ferromagnetism, other Q-silicon properties of interest include enhanced hardness and superconductivity, Narayan says.
“This discovery of Q-silicon stands to revolutionize modern microelectronics by adding new functionalities, such as spintronics, or spin-based quantum computing,” Narayan said. “Modern microelectronics is based upon the charge of an electron, making them relatively slow with limited mobility. By using Q-silicon, we make use of the spin of the electron, making computers much faster with negligible power consumption.
“In short, Q-silicon provides an ideal platform for integration of spintronics with microelectronics on a chip.”