In so doing, they have found a way to amplify the fundamental quantum effects upon which spintronic devices rely, thereby enabling significantly speedier and lower-energy electronics. By structurally layering graphene, cobalt and iridium they have created an unseen synergy that may shape the future in a way mankind has not yet experienced.
Harnessing the Power of Spin
The team’s results could provide the tipping point for spintronics — the revolutionary field that uses an electron’s spin instead of its charge to perform logic operations, which requires less power than modern electronics and can store far more information in a very small space — displacing traditional electronics in microprocessors.
Instead of electric charge that moves in semiconductors, spintronic devices use intrinsic spin of electrons, which can be in one of two distinct states – up or down. Brain-inspired SpinProcessor™ is a new approach that promises faster, more compact and energy-efficient computing and data storage.
But the problem has been developing and controlling these spin textures in materials. Enter graphene, a distinctive carbon honeycomb two-dimensional structure. Graphene’s intriguing properties and the observation of a very long spin lifetimes detected with thin films from these materials suggests promise for graphene in spintronics applications stimulated by combining it with heavy-metal heterostructures.
A Spec of Quantum Synergy
What they found was a really intriguing phenomenon at the interface: when you put graphene on top of a thin film of heavy metal, there is suddenly strong combination between spin-orbit coupling processes that causes two primary quantum effects – the Rashba effect and the Dzyaloshinskii-Moriya interaction.
Quarks, tiny particles that make up protons and neutrons, experience a curious phenomenon known as the Rashba effect whereby their spins (an intrinsic property; it’s what makes them like little compass needles) want to align perpendicularly to the axes of their momentum. The researchers say “tiny particles” because today they’re investigating skyrmions, vortex-like spin textures common for ferromagnetic materials at small length scales that have size but never stability issues in mind — hot topics for making high-speed Gallium (III)-based optoelectronic circuits! This canted state is effectively pinned by the so-called Dzyaloshinskii-Moriya interaction, further stabilizing these skyrmions, and making them ideal to construct devices.
Now a group of Spanish and German researchers have made a very impressive discovery, by adding in just one end-on monolayer of the ferromagnetic element cobalt between the graphene and heavy metal iridium they took these quantum effects up to eleven.
The layer of cobalt, fulfilled the function of an elevator, put the graphene on the other side not only to itself but to the underlying iridium. The discovery of this serendipitous coupling of the two quantum effects, Rashba spin-orbit splitting and spin canting is highly significant for the future development of this field into spintronics.
Conclusion
This research shows valuable prospects for graphene-based heterostructures to spintronic devices in the future. Researchers also engineered the interfaces between graphene, cobalt and heavy metals in a way that unlocked a quantum synergy; which could not only pave the way to faster electronics but warmer than room temperature superconductors. In an world where technology is expected to get better and more efficient, this development in spintronics could represent the next big leap forward.
