The use of electron spin enhances data encoding.
Remember flip-phones. Spintronics, a rapidly developing field of research that promises to revolutionize how electronic devices transmit and receive signals, may make smartphones obsolete.
Data is encoded in most modern technologies as either a zero or one, depending on how many electrons reach the capacitor. Data is also transferred using spintronics according to the direction in which these electrons spin.
A team of researchers from Duke University and Weizmann Institute, led by Michael Therien (Professor of Chemistry at Duke), report on a breakthrough in the field. They have developed a conducting system that controls the electron spin and transmits spin current over long distances. This is without needing to use traditional spin conductors’ ultra-cold temperatures.
“The structures that we present here are fascinating because they determine new strategies to generate large-magnitude spin currents at ambient temperature,” stated Chih Hung Ko, the first author, and recent Duke Chemistry Ph.D.
Electrons behave like spinning tops. Spin-up electrons rotate counterclockwise. Although electrons can have opposite spins, they can share the same volume. However, electrons that spin in the same direction repel each other, just like magnets of identical polarity.
Scientists can control the spin of electrons along currents to encode new information in an electric signal.
Instead of turning capacitors on/off in a binary fashion, spintronics devices could send signals according to electron spin. Spin-up might be a different thing than spin-down.
David Beratan (Duke professor of chemistry and physics and co-author of this paper) said, “Since spin can be up/down, that’s an information piece that’s not harvested by conventional electronic devices.”
Ordinary device currents contain equal amounts of spin-up electrons and spin-down electrons. Creating a draft composed of one spin at room temperature is challenging. The spins turn around, collide with each other, fall out of line and deform the signal, much like a bad game on the telephone.
Therien and his team now have a strategy for building molecular conductors. This ensures that electrons are in sync and propagate the spin direction over long distances. This allows signals to be transmitted at high fidelity and room temperature.
Beratan stated, “It’s all in the persistence of that spin Polarization.” These spins can be jostled about, interact with surrounding molecules, and flip themselves. Their spin orientation is maintained over long periods and long distances. They are in line.
A particular class of chiral molecules can filter out electrons spinning in the wrong direction.
Chiral molecules are distinguished by their handedness. These molecules mirror each other, much like our right and left hands. These molecules can be either left-handed or right-handed, and their handedness acts as a filter to allow electron spins to pass through. Element spins in the opposite direction to the molecule’s handedness are filtered out, just like how you would be ejected from the treadmill if your walking was not in the correct order.
His team had already created molecular wires, which are molecules that are daisy-chained together in a wire-like manner. These structures can quickly produce electric charges. The team modified these molecular wires with chiral elements to create a system that transmits control at meager resistance and transmits the same spin as all electrons.
Therien stated, “We have integrated for the first-time charge propagating as well as spin polarizing functions into the same molecular wire.”
Ron Naaman, a professor at Theismann Institute, said that his laboratory built devices using Therien’s molecules. This system has tremendous potential to encode and transmit information.
These molecular wires transmit spins at ambient temperature, making them promising for new technology development.
Therien stated that it could selectively transmit spin at room temperatures over long distances without dephasing. This opens up possibilities for more devices and could be useful for quantum information science.
Beratan stated that cooling your computer with liquid Nitrogen would not be practical. “If we could efficiently process spins at room temperatures, it would be a real breakthrough in their practical use.”