Ars
Technica: Because electron spin is a simple binary
state—either up or down—it has potential for
quantum computing, but systems for maintaining and controlling
spin states have been hard to implement. A team of researchers
from the University of New South Wales in Sydney, Australia,
has achieved relatively long-duration electron spin states
using phosphorus embedded in silicon. The researchers found
that phosphorus, with just a single electron in its outer
shell, is an excellent host for single spins, while crystals of
silicon, being next to phosphorus in the Periodic Table, is an
excellent host for phosphorus atoms. Working at just 0.3 K and
in a strong magnetic field, the researchers used microwave
pulses to initialize the electron spin state, which remained
coherent for up to 0.2 ms. That duration is more than long
enough for the operation of electronics, and the setup serves
as proof of concept for the use of spin-based quantum computing
systems.
