This story was originally published in @TheU.
Traditional electronics use semiconductors to transmit data through bursts of charged carriers (electrons or holes) to convey messages in “1s” and “0s.” Spintronic devices can process an order of magnitude more information by assigning binary code to the orientation of electrons’ magnetic poles, a property known as spin— an “up” spin is a 1, a “down” is a 0.
A major barrier to commercial spintronics is setting and maintaining the electron spin orientation. Most devices tune spin-orientation using ferromagnets and magnetic fields, a burdensome and unreliable process. Decades of research has shown that carriers lose their spin orientation moving from materials with high-conductivity to low-conductivity—for example, from metallic ferromagnets to undoped silicon and conjugated polymer materials that make up most modern semiconductors.
For the first time, scientists transformed existing optoelectronic devices into ones that can control electron spin at room temperature, without a ferromagnet or magnetic field.
Most optoelectronic devices, such as LEDs, only control charge and light but not the spin of the electrons. In the new study led by the University of Utah physicists and researchers at the National Renewable Energy Laboratory (NREL), replaced the electrodes of store-bought LEDs with a patented spin filter, made from hybrid organic-inorganic halide perovskite material. The LEDs produced circularly polarized light, a tell-tale sign that the filter had injected spin-aligned electrons into LED’s existing semiconductor infrastructure, a massive step forward for spintronics technology.
“It’s a miracle. For decades, we’ve been unable to efficiently inject spin-aligned electrons into semiconductors because of the mismatch of metallic ferromagnets and non-magnetic semiconductors,” said Valy Vardeny, Distinguished Professor in the Department of Physics & Astronomy at the U and co-author of the paper. “All kinds of devices that use spin and optoelectronics, like spin-LEDs or magnetic memory, will be thrilled by this discovery.”
The study was published in the journal Nature on June 19, 2024.
