New STM Microscope To Study Propeties of Electron Spin

Jun 23, 2004

University of Arkansas scientists seek to harness an electron's spin to create tiny machines with large memories. To do this, they have built a microscope that may allow them to be the first researchers to measure the properties of electron spin injection in conducting materials.

Electrons have spin in addition to charge, but in the past this property has been little used or studied. By understanding and using the different states achieved when an electron's spin rotates, researchers could potentially increase information storage a million fold. This would allow vast quantites of information to be stored in a space the size of a sugar cube or transmitted from one tiny device to another in the blink of an eye.

Today's transistors store information by using two different states to save data or create words on the computer. Each bit in a given piece of information-a word or a computer program-can either be "on" or "off," meaning that the possibilities are based on two, or binary logic. However, the different states created when an electron's spin rotates could allow researchers to increase that base number from two to 10. This would create massive information storage and transmission capabilities.

Paul Thibado, associate professor of physics, won a $370,000 grant from the National Science Foundation to measure the properties of a spin-based transistor using a customized, two-tip Scanning Tunneling Microscope (STM) system. This work builds on a previous NSF grant of $760,000, which was used to create the customized STM.

Researchers currently use STMs to inject electrons of a certain spin into a conducting material. However, they have not been able to study what happens to the electrons as they pass through the material because they would need a second STM to create a transistor, a miniature electronic switch used to power televisions, cars, radios, home appliances and computers. A traditional transistor consists of a source, a drain and a gate. When an electric field is placed on the gate, current moves from the source to the drain. Placing two STM tips next to one another won't work-the tips remain too far apart to create a transistor.

Thibado and his colleagues proposed building a different kind of instrument, one with two STMs placed at right angles to one another. This allows the tips to get close enough-about 10 nanometers apart-to create an effective detection device. Thibado and his colleagues will use one tip to inject electrons of a certain spin into a surface, while the other acts as a detection device, reading the actual spin of the injected electrons. By applying a magnetic field, the researchers can then change the electrons' spins, creating a field-effect transistor.

First, however, the researchers must learn more about how spin works, and Thibado's new equipment will allow that to happen. The UA team will use the modified instruments to measure the current and voltage properties of a spin-dependent transistor, examine the characteristics of the transistor at different temperatures and change the distance between the two STMs to determine the device's effectiveness at various distances. They also will use different materials on the tip of the STMs to determine how they affect the transistor's properties.

More information at advancement.uark.edu/

Explore further: The latest fashion: Graphene edges can be tailor-made

add to favorites email to friend print save as pdf

Related Stories

Better data needed to make good immigration policy

Jan 14, 2015

As debates rage about the legal status of immigrants, researchers still lack enough data—and enough of the right data—to help policy makers make better, more informed decisions, according to a team of sociologists and ...

Extrasolar storms: How's the weather way out there?

Jan 13, 2015

Orbiting the Earth 353 miles above the ground, the Hubble Space Telescope silently pivots toward its new target. At the same time, flying 93 million miles away in interplanetary space, NASA's Spitzer Space ...

Quantum hard drive breakthrough

Jan 08, 2015

Physicists developing a prototype quantum hard drive have improved storage time by a factor of more than 100.

Recommended for you

The latest fashion: Graphene edges can be tailor-made

Jan 23, 2015

Theoretical physicists at Rice University are living on the edge as they study the astounding properties of graphene. In a new study, they figure out how researchers can fracture graphene nanoribbons to get ...

Nanotechnology changes behavior of materials

Jan 23, 2015

One of the reasons solar cells are not used more widely is cost—the materials used to make them most efficient are expensive. Engineers are exploring ways to print solar cells from inks, but the devices ...

Gold 'nano-drills'

Jan 22, 2015

Spherical gold particles are able to 'drill' a nano-diameter tunnel in ceramic material when heated. This is an easy and attractive way to equip chips with nanopores for DNA analysis, for example. Nanotechnologists ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.