Computers Could Run Faster With Spinning Electrons
A conventional computer processor.
CREDIT: Barbara Kennedy, Penn State University
Forget external hard drives and more RAM; if you really want to upgrade your computing rig, it’s time to get your electrons spinning in the right direction. New research in the field of “spintronics” suggests that changing the spin of the electrons in an internal processor is the best way to get your computer running quickly.
According to Nitin Samarth, a professor of physics at Pennsylvania State University, advancements in computing speeds slowed down about five years ago because of limitations in the way computer processors are made.
Today’s processors rely on the density of transistors on a computer chip. The transistors act like switches, turning “on” or “off” – corresponding to a “one” or “zero” state – to change the flow of electrons through the chip. The more tightly packed the transistors are on a chip, the faster the flow of electrons through the processor. So tightly packed transistors make computers run faster. But all those moving electrons create a lot of heat.
“The very fundamental limitation that stops computer manufacturers from making these chips faster is that the transistors are reaching the density at which the heat they generate cannot dissipate fast enough to prevent the computer from melting,” Samarth said.
Samarth and his team have been working on giving computers a new way to get their ones and zeros. Instead of having electrons flow hotly through a transistor, the scientists have designed new kinds of materials that will let individual electrons be “cool” by just spinning in one of two opposite ways.
"In one of those mysterious aspects of quantum mechanics, Nature allows the electron only to either spin up or spin down in the presence of a magnetic field," Samarth said.
Samarth and his team of researchers have been trying to cool down the process of creating super-fast transistors, and they’re doing it one electron at a time.
“One of the interesting phenomena that people discovered in recent years is that you can change the orientation of an electron’s spin just by using a voltage,” Samarth said. “You are not back to creating heat-generating resistance inside a transistor by making the electrons flow, but rather you are just changing the orientation of their spin.”
These electron-manipulating transistors could pave the way to faster, more energy-efficient computers, according to Samarth. But first, he and his team need to build them.
“It’s a little bit like playing atomic-scale Legos,” said Samarth of the process of creating “spintronic” transistors. “Like the components in modern computer chips, the highly specialized devices that we are fabricating here, which might function as spintronics transistors, typically are smaller than 100 times the width of one strand of your hair.”
Samarth uses two ultra-high-vacuum chambers to perform a process known as molecular-beam epitaxy.
“At first we create a very high-vacuum inside these chambers, then we deposit beams of selected kinds of elements in a very controlled way in order to deposit a layer of material that is the thickness of only one atom,” Samarth said.
“Because of the ultra-high vacuum, while one atomic layer is going down, nothing else is being deposited...We then can use a variety of different elements, plus the power of thermodynamics and chemistry, to engineer the crystal we want by building it up one atomic layer at a time.”
In addition to the creation of these “spintronic” transistors, the researchers are also working on manipulating electron spin in other semiconducting devices.