Material could change the future of spintronics
A University of Utah-led team has discovered that a class of materials called organic-inorganic hybrid perovskites could be a game changer for future spintronic devices. Spintronics uses the direction of the electron spin - either up or down - to carry information in ones and zeros. A spintronic device can process exponentially more data than traditional electronics that use the ebb and flow of electrical current to generate digital instructions. But physicists have struggled to make spintronic devices a reality.
The new study, published in Nature Physics, is the first to show that organic-inorganic hybrid perovskites are a promising material class for spintronics. The researchers discovered that the perovskites possess two contradictory properties necessary to make spintronic devices work - the electrons' spin can be easily controlled, and can also maintain the spin direction long enough to transport information, a property known as spin lifetime.
"It's a device that people always wanted to make, but there are big challenges in finding a material that can be manipulated and, at the same time, have a long spin lifetime," says Sarah Li, assistant professor in the Department of Physics & Astronomy at the U and lead author of the study. "But for this material, it's the property of the material itself that satisfies both."
Organic-inorganic hybrid perovskites is already famous in scientific circles for being amazingly efficient at converting sunlight into electricity.
"It's unbelievable. A miracle material," says Z. Valy Vardeny, distinguished professor in the Department of Physics & Astronomy and co-author of the study, whose lab studies perovskite solar cells. "In just a few years, solar cells based on this material are at 22 percent efficiency. And now it has this spin lifetime property. It's fantastic."
The material's chemical composition is an unlikely candidate for spintronics, however. The hybrid perovskite inorganic frame is made of heavy elements. The heavier the atom, the easier it is to manipulate the electron spin. That's good for spintronics. But other forces also influence the spin. When the atoms are heavy, you assume the spin lifetime is short, explains Li.
"Most people in the field would not think that this material has a long spin lifetime. It's surprising to us, too," says Li. "We haven't found out the exact reason yet. But it's likely some intrinsic, magical property of the material itself."