Researchers have created a spin capacitor that can generate and hold the spin state of electrons for a number of hours. Previous attempts have only held the spin state for a fraction of a second. In electronics, a capacitor holds energy in the form of electric charge. A spin capacitor is a variation on that idea. Instead of holding just charge, it also stores the spin state of a group of electrons; in effect, it freezes the spin position of each of the electrons.
The ability to capture the spin state opens up the possibility that new devices could be developed that store information so efficiently that storage devices could get very small. A spin capacitor measuring just one square inch could store 100 terabytes of data.
Currently, up to 70 percent of the energy used in an electronic device, such as a computer or mobile phone, is lost as heat and that is the energy that comes from electrons moving through the device’s circuitry. It results in huge inefficiencies and limits the capabilities and sustainability of current technologies. Research shows that the devices of the future may not have to rely on magnetic hard disks. Instead, they will have spin capacitors that are operated by light, which would make them very fast, or by an electrical field, which would make them extremely energy-efficient.
In conventional computing, information is coded and stored as a series of bits; for example, 0s and 1s on a hard disk. Those 0s and 1s can be represented or stored on the hard disk by changes in the polarity of tiny magnetized regions on the disk. With quantum technology, spin capacitors could write and read information coded into the spin state of electrons by using light or electric fields.
The research team was able to develop the spin capacitor by using an advanced materials interface made of a form of carbon called buckminsterfullerene (buckyballs), manganese oxide, and a cobalt magnetic electrode. The interface between the nanocarbon and the oxide is able to trap the spin state of electrons. The time it takes for the spin state to decay has been extended by using the interaction between the carbon atoms in the buckyballs and the metal oxide in the presence of a magnetic electrode.
The team believes the advances can be built upon, most notably towards devices that are able to hold spin state for longer periods of time.