Lighting the Way to New Technologies
Researchers at MIT have devised a new way to measure the properties of a solid material. To understand how any material will interact with another one must understand how the electrons behave. Traditionally this is determined by shining a light onto the material to see how the electrons react at a specific point. To get information on the entire material, it is shifted slightly and the process repeats. This can take a very long time, which is why the MIT researchers were looking for something new.
Though electrons are single particles with a single charge, they do act like bar magnets and the direction of the 'magnet' is called spin. The new method takes advantage of that spin by shining a circularly polarized laser at the material. An electron’s spin determines in what direction it will drive and how fast it will move due to the laser. Pulsing the laser allows the researchers to determine, the energy, momentum and spin of the electrons it hit in three dimensions.
This technique was developed to analyze topological insulators but may impact far more. Topological insulators are curious material which conduct electricity on their surface, but are insulators inside. They have the potential to reduce the heat put out by electronics because their resistance is not greatly affected by impurities. Regular metals will see their resistances increase with impurities, and their resistance will cause the metal to heat up.
This technology could also be used to create a new kind electromagnetic storage where light is used to flip a bit, instead of an electronic interaction. The fact that light can selectively push away electrons of particular spins, leaving a current of other spins, can be very useful in the future. The potential for this new technique, like topological insulators, is still being discovered as researchers envision new futures.