Study Confirms Magnetic Properties of Silicon Nano-Ribbons

Think of a magnetic material and iron, nickel or cobalt will inevitably come to mind – but silicon?

In this otherwise non-magnetic material, scientists from the US Department of Energy’s Oak Ridge National Laboratory have succeeded in creating magnetic ordering along the edges of gold-stabilised silicon surfaces. The key to the magnetic ordering lies with the electron spins at the broken bonds of these surfaces. The spin of an electron refers to it’s intrinsic angular momentum (like linear momentum, but for a rotating object) which, because of the restraints placed upon it by quantum mechanics, can only have one of two values – “spin up” or “spin down”. The data gathered by the scientists has proven that along the edges of the sheets of silicon atoms there was a regular up-down-up-down arrangement of spins, which gave magnetic properties to the material.

Admittedly, the magnetisation of a few rows of atoms on the edge of a sheet of silicon may not sound like it’s going to change our world, but nano-scale experiments such as these could have exciting implications for everyday technology. Digital data storage systems are based on our ability to encode data such as text and pictures as a series of 1’s and 0’s, which correspond to transistors either being “on” or “off”. The fact that scientists have been able to precisely map the alternating up-down-up-down electron spins along the edge of their sheet of silicon atoms brings us a step close to being able to use “spin up” and “spin down” as analogues of today’s “on” and “off” way of encoding data. Despite the difficulties associated with trying to pin down the spin states of individual particles, with something of the order of 10¹⁵ atoms per cm² it is clear to see that storing data in this way would be very efficient. And in our desire for ever small gadgets and technologies, the magnetisation of a few rows of silicon atoms may lead to data encoding on an atomic scale becoming a part of our everyday lives.

http://iopscience.iop.org/1367-2630/14/10/103004