How to Store and Then Read Data in the Spins of Atomic Nuclei
For the experiments, McCamey, Boehme and colleagues used a thin, phosphorus-doped silicon wafer measuring 1 millimeter square, and placed electrical contacts on it. The device was inside a supercold container, and surrounded by intense magnetic fields. Wires connected the device to a current source and an oscilloscope to record data.
The physicists used powerful magnetic fields of 8.59 Tesla to align the spins of phosphorus electrons. That's 200,000 times stronger than Earth's magnetic field.
Then, pulses of near-terahertz electromagnetic waves were used to "write" up or down spins onto electrons orbiting phosphorus atoms. Next, FM-range radio waves were used to take the spin data stored in the electrons and write it onto the phosphorus nuclei.
Later, other pulses of near-terahertz waves were used to transfer the nuclear spin information back into the orbiting electrons, and trigger the readout process. The readout is produced because the electrons' spins are converted into variations in electrical current.
"We read the spin of the nuclei in the reverse of the way we write information," Boehme says. "We have a mechanism that turns electron spin into a current."
Summarizing the process, Boehme says, "We basically wrote 1 in atoms' nuclei. We have shown we can write and read [spin data in nuclei]," and shown that the information can be repeatedly read from the nuclei for an average of 112 seconds before all the phosphorus nuclei lose their spin information. In a much shorter time, the physicists read and reread the same nuclear spin data 2,000 times, showing the act of reading the spin data doesn't destroy it, making the memory reliable, Boehme says.
Reading out the data stored as spin involved reading the collective spins
|Contact: Lee Siegel|
University of Utah