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University of Waterloo chemists have discovered that light can induce magnetization in certain semiconductors – the standard class of materials at the heart of all computing devices today.
Their results, which appeared recently in Nature Nanotechnology, could pioneer a fundamentally new way for electronic devices to process, transfer, and store information that is much faster and more efficient than conventional semiconductors.
“We’ve basically magnetized individual semiconducting nanocrystals (tiny particles nearly 10,000 times smaller than the width of a human hair) with light at room temperature,” said Pavle Radovanovic, a professor of Chemistry and a member of the Waterloo Institute for Nanotechnology. “It’s the first time someone’s been able to use collective motion of electrons, known as plasmon, to induce a stable magnetization within such a non-magnetic semiconductor material.
For decades, computer chips have been shrinking thanks to a steady stream of technological improvements in processing density. Experts have, however, been warning that we’ll soon reach the end of the trend known as Moore’s Law, in which the number of transistors per square inch on integrated circuits double every year.
“Simply put, there’s a physical limit to the performance of conventional semiconductors as well as how dense you can build a chip,” said Radovanovic. “In order to continue improving chip performance, you would either need to change the material transistors are made of - from silicon, say to carbon nanotubes or graphene - or change how our current materials store and process information.”
Radovanovic’s finding is made possible by magnetism and a field called spintronics, which proposes to store binary information within an electron’s spin direction, in addition to its charge and plasmonics, the collective oscillations of electrons in a material.
In manipulating plasmon in doped indium oxide nanocrystals Radovanovic proves that the magnetic and semiconducting properties can indeed be coupled, all without needing ultra-low temperatures (cryogens) to operate a device.
He anticipates the findings could initially lead to highly sensitive magneto-optical sensors for thermal imaging and chemical sensing. In the future, he hopes to extend this approach to quantum sensing, data storage, and quantum information processing.
The project was funded by the Natural Sciences and Engineering Research Council of Canada and the Canada First Excellence Research Fund in Transformative Quantum Technologies.