Scientists build 'magnetic semiconductors' one atom at a time

Spintronics at the atomic level. Substitution of magnetic atoms (manganese) into a semiconductor (gallium arsenide) creates the material for future electronics. Spins of the magnetic atoms interact via a cloud... Click here for more information.

Princeton, N.J. -- In a stride that could hasten the development of computer chips that both calculate and store data, a team of Princeton scientists has turned semiconductors into magnets by the precise placement of metal atoms within a material from which chips are made.

The effort marks the first time that scientists have achieved this degree of control over the atomic-level structure of a semiconductor, a goal that has eluded researchers for many years. The team used this unique capability to make a semiconductor magnetic, one atom at a time. Team leader Ali Yazdani said that manipulating semiconductors could eventually revolutionize computers by exploiting not just the flow of electrons but also their quantum property, called spin, for computation.

"Using the tip of a scanning tunneling microscope, we can take out a single atom from the base material and replace it with a single metal that gives the semiconductor its magnetic properties," said Yazdani, a Princeton professor of physics. "The ability to tailor semiconductors on the atomic scale is the holy grail of electronics, and this method may be the approach that is needed."

The team, which also includes scientists from the University of Illinois at Urbana-Champaign and the University of Iowa as well as Princeton, will publish their results as the cover article of the July 27 issue of the scientific journal, Nature.

By incorporating manganese atoms into the gallium arsenide semiconductor, the team has created an atomic-scale laboratory that can reveal what researchers have sought for decades: the precise interactions among atoms and electrons in chip material. The team used their new technique to find the optimal arrangements for manganese atoms that can enhance the magnetic properties of gallium arsenide. Implementation of their findings within the chip manufacturing process could result in a major advance in the use of both the magnetic "spin" as well as electric charge for computation.