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: Photo-initiated charge separation in nanobiohybrid complex

add to favorites email to friend print save as pdf

Related Stories

Quantum mechanics to charge your laptop?

Sep 18, 2014

Top scientists from UC Berkeley and MIT found the expertise they lacked at FIU. They invited Sakhrat Khizroev, a professor with appointments in both medicine and engineering, to help them conduct research ...

Invisibility cloaks closer thanks to 'digital metamaterials'

Sep 15, 2014

The concept of "digital metamaterials" – a simple way of designing metamaterials with bizarre optical properties that could hasten the development of devices such as invisibility cloaks and superlenses – is reported in a paper published today in Nature ...

Watching the winds where sea meets sky

Aug 14, 2014

The ocean covers 71 percent of Earth's surface and affects weather over the entire globe. Hurricanes and storms that begin far out over the ocean affect people on land and interfere with shipping at sea. ...

Recommended for you

Photo-initiated charge separation in nanobiohybrid complex

26 minutes ago

In natural systems, electron flow is mediated by proteins that spatially organize donor and acceptor molecules with great precision. Achieving this guided, directional flow of information is a desirable feature ...

Engineered proteins stick like glue—even in water

20 hours ago

Shellfish such as mussels and barnacles secrete very sticky proteins that help them cling to rocks or ship hulls, even underwater. Inspired by these natural adhesives, a team of MIT engineers has designed ...

Smallest possible diamonds form ultra-thin nanothreads

20 hours ago

For the first time, scientists have discovered how to produce ultra-thin "diamond nanothreads" that promise extraordinary properties, including strength and stiffness greater than that of today's strongest ...

A nanosized hydrogen generator

Sep 20, 2014

(Phys.org) —Researchers at the US Department of Energy's (DOE) Argonne National Laboratory have created a small scale "hydrogen generator" that uses light and a two-dimensional graphene platform to boost ...

User comments : 0