If you are a recent reader of
this column or other sources
of electronics news, you
know that we are approaching a
“silicon crisis.” Moore’s Law, the
regular doubling of the number
of transistors that can be fabricated
on a silicon chip of a given
size, has nearly run its course for
reasons that we have covered
We saw that one way to postpone this day of
reckoning might be the use of carbon nanotube
field effect transistors or CNFETS. But this would
only be a postponement. Tomorrow’s real breakthrough
computing technologies are currently being
developed by one of the oldest computer companies
in the United States.
ON THE RESEARCH FRONT
A recent development emerging from IBM Research
is nothing short of startling: digital ones and
zeros have been stored and retrieved from an array
of just 12 iron atoms implanted in a special type of
A group at IBM’s Almaden Research Center in
Silicon Valley created a unit of magnetic storage by
arranging two rows of six iron atoms each on a substrate
of copper nitrite atoms, which are clustered
quite tightly together furnishing “magnetic insulation”
from other such iron clusters because they
When ferromagnetic materials like iron and
nickel are magnetized, the magnetic moments of
the individual atoms, which are defined by the
spins of their electrons, are magnetically aligned.
That is, the spins of the electrons of a given atom
are aligned with like electron spins of neighboring
atoms, so their north poles all point in one direction
and their south poles all point in the opposite
direction. The net effect is that when a piece of ferromagnetic
material is magnetized, it has a north
pole and a south pole, causing it to display magnetic
In antiferromagnetic materials, the spins of individual
atoms are aligned with neighbors having opposite
spins. The result is that the north and south
poles of the individual atoms effectively cancel
each other out, rather than reinforcing each other.
Their mutual polar attractions cause them to be
tightly compacted on the atomic level, and a piece
of antiferromagnetic material does not display magnetic
This property prevents individual ferromagnetic
clusters from interfering with each other, facilitating
|Researchers working at NIST have confirmed that thin magnetic
layers (red) of a semiconductor separated by a nonmagnetic layer (blue)
can exhibit a coveted phenomenon known as ‘antiferromagnetic coupling,’
in which manganese (Mn) atoms in successive magnetic layers
spontaneously orient their magnetization in opposite directions. This
discovery, made by scattering neutrons (arrows) from the material, raises the prospects of ‘spintronic logic circuits’ that could both store and process data.
In the IBM research, one bit of data was stored in
just 12 iron atoms, as opposed to a contemporary
hard drive, which stores a single bit of data in about
a million atoms.
The implications of this are apparent, but the
process is a long way from being commercialized.
In the IBM experiment, the storage medium was held close to absolute
zero; and a scanning, tunneling microscope was used to manually
configure the atoms to store the data bits. The experimenters have
said that the same result could be achieved at room temperature using
about 150 iron atoms. IBM claims that this harbors the potential
for storage 100 times denser than today’s hard disks.
Perhaps the most scientifically interesting aspect of this work is
the fact that even smaller groups of atoms begin to exhibit quantum
mechanical behavior, simultaneously existing in both spin states, so
they simultaneously represent both ones and zeros.
This has been analogized to a loop in which a given current flows
counterclockwise, while another current simultaneously flows clockwise.
Atoms such as these may be assembled into so-called quantum
bits or qubits, opening the door to the slightly bizarre world of quantum
Like most things dealing with quantum
mechanics, this is almost incomprehensible.
To quote Niels Bohr, “If anybody says he
can think about quantum physics without
getting giddy, that only shows he has not
understood the first thing about them.”
IBM experimenters are making superconducting
qubits, in a so-called “delusion
refrigerator,” which can achieve temperatures
of 15–20 milliKelvins; that is,
0.015–0.020 degree Celsius above absolute
zero. At this temperature, a qubit starts at
its quantum ground state and can be kept
“pure” for a longer time before it degenerates
into a single-state bit.
The goal is to produce a “logical qubit,”
i.e., one that never degenerates. To
repeat, a qubit is a bit that exists in both
logical states, one and zero, simultaneously.
Remember Niels Bohr.
This is highly experimental, but experimenters
feel that a stable quantum
computer may be realized within 10 or
15 years, although it sounds like science
fiction, if not outright fantasy, today.
To give an idea of what this might
mean, a 250-qubit quantum computer
could hold more bits than there are particles
in the universe. Another example
is factoring a 1000-digit decimal number.
This might take existing computers
the age of the universe to perform, but
a quantum computer of appropriate size
might do this task in an hour. This would,
of course, render most current encryption
Nanoelectronic storage and quantum
computing are just laboratory experiments
now, but things are happening
quickly, and sooner or later they will be
technology we can use.
So as we stand at the historical place
where we can see the end of Moore’s
Law just down the road, we also see
some very exciting new breakthroughs
in electronics out there.
Fasten your seat belts; it’s going to be
a wild ride!
Randy Hoffner is a veteran of the big
three TV networks. He can be reached
through TV Technology.