PORTLAND, Ore.Research funded by Intel Corp. and others has led to a spintronic breakthrough that encodes information on the spin of electronseither "up" or "down"instead of charge, enabling ultra-low-power operation for nonvolatile circuitry that remembers its state even when turned off.
The promising new spintronic material category called a dilute magnetic semiconductor (DMS) until now required manganese doped compound semiconductors such as indium arsenide or gallium arsenide. Now researchers say they have found that germanium quantum dots enable electric field controlled ferromagnetism in a material compatible with conventional CMOS.
"We've achieved success on electric field"controlled ferromagnetism at 100 degrees Kelvin and are moving towards room temperature," said Kang Wang, an electrical engineering professor at the University of California-Los Angeles (UCLA). Wang performed the work with UCLA senior researcher Faxian Xiu, with contributions from professor Jin Zou and postdoctoral fellow Yong Wang at the Australia's University of Queensland.
Ferromagnetism is the mechanism by which spin is encoded onto electrons. Conventional methods of creating a magnetic field require passing a power hungry electrical current through a coil. The UCLA researchers think that they can impart spin using the same ferromagnetic mechanism, but with a simple electric field that does not require current to conduct, thereby enabling ultra-low power consumption for its spintronic devices.
Electric-field controlled ferromagnetism was achieved by growing germanium quantum dots on p-type silicon substrate, which they used as the channel layer of a demonstration metal-oxide semiconductor whose applied electric field imparted spin to the electrons passing through it.
Funding for the project was provided by Intel, the Australian government, the Center for Functional Engineered Nano Architectronics (FENA) and the Western Institute of Nanoelectronics (WIN) at UCLA Engineering.