Researchers around the world are working on alternatives to miniaturisation. A particularly promising approach involves spin electronics.
In their experiment, the researchers demonstrated the production, transport and detection of electronic spins in the boundary layer between lanthanum-aluminate and strontium-titanate.
In this material system, a thin, electrically conducting layer forms at the interface between the two non-conducting materials: a 2D electron gas.
The team has now shown that this electron gas transports not only charge, but also spin. “To achieve this we first had to surmount several technical hurdles,” says Dr Hans Hübl, deputy director of the Walther-Meißner-Institute. “The two key questions were: How can spin be transferred to the 2D electron gas and how can the transport be proven?”
The scientists solved the problem of spin transfer using a magnetic contact. Microwave radiation forces its electrons into a precession movement. This motion does not last forever, but rather, weakens in time – in this case by imparting its spin onto the electron gas.
The electron gas then transports the spin information to a non-magnetic contact located one micrometre next to the contact. The non-magnetic contact detects the spin transport by absorbing the spin, building up an electric potential in the process.
Measuring this potential allowed the researchers to systematically investigate the transport of spin and demonstrate the feasibility of bridging distances up to one hundred times larger than the distance of today’s transistors.