Select your localized edition:

Close ×

More Ways to Connect

Discover one of our 28 local entrepreneurial communities »

Be the first to know as we launch in new countries and markets around the globe.

Interested in bringing MIT Technology Review to your local market?

MIT Technology ReviewMIT Technology Review - logo


Unsupported browser: Your browser does not meet modern web standards. See how it scores »

{ action.text }

Altered states: As the electric field induced by a silicon nanowire (gray) increases, an electron in an arsenic atom moves from its ground state (left) to an excited state (right). During this transition, the electron enters a hybridized state (middle) in which it is in both of the other states simultaneously. In theory, such an electron could serve as a “qubit” in a quantum computer.

Depending on the strength of the electric field created by the top nanowire, an electron could be found in one of three states. At low electric fields, the electron remained bound to the arsenic atom. At high electric fields, the electron was pulled away from the atom. But when the electric field was at just the right level, the electron would be in both places at once.

In order for a quantum computer to work, its qubits–the quantum equivalent of a classical computer’s bits–need to be “entangled”: their quantum states have to be coupled with each other. Pulling an electron away from its atom “might be an interesting way to couple” adjacent qubits, says Schenkel.

“While this result is an important one, the real challenge to making future single-dopant devices is in figuring out how to position the [arsenic atoms] into the silicon host with the required precision,” says Bruce Kane, a research scientist at the University of Maryland. The researchers found their six devices by chance; to produce working circuits, they would need to be able to position atoms of arsenic–or some other material–in the transistors more reliably.

While the researchers eventually hope to be able to control the position of the atoms in the transistor, “our next step is to add a second electron and see what happens to the configuration of the electron state,” says Gabri Lansbergen, another Delft researcher. “In the far future,” Rogge adds, “we would like to experiment with several [materials] and see how they interact.”

0 comments about this story. Start the discussion »

Credits: Insoo Woo and Rajib Rahman, Purdue University

Tagged: Computing, silicon, transistors, quantum computer

Reprints and Permissions | Send feedback to the editor

From the Archives


Introducing MIT Technology Review Insider.

Already a Magazine subscriber?

You're automatically an Insider. It's easy to activate or upgrade your account.

Activate Your Account

Become an Insider

It's the new way to subscribe. Get even more of the tech news, research, and discoveries you crave.

Sign Up

Learn More

Find out why MIT Technology Review Insider is for you and explore your options.

Show Me