Negative voltage instead flips the spins of the chromium oxide down, with the spin orientation of the graphene’s current flipping to the right and generating a signal clearly distinguishable from the other. When applying positive voltage, the spins of the underlying chromium oxide point up, ultimately forcing the spin orientation of the graphene’s electric current to veer left and yield a detectable signal in the process. Crucially, chromium oxide is magneto-electric, meaning that the spins of the atoms at its surface can be flipped from up to down, or vice versa, by applying a meager amount of temporary, energy-sipping voltage. Fortunately, Binek had already dedicated years to studying and modifying just such a material, chromium oxide. To do it, the researchers needed to underlay the graphene with the right material. Actually controlling the orientation of those spins, using substantially less power than a conventional transistor, was a much more challenging prospect. The team knew that electrons flowing through graphene, an ultra-robust material just one atom thick, can maintain their initial spin orientations for relatively long distances - an appealing property for demonstrating the potential of a spintronic-based transistor. So rather than depend on electric charge as the basis of its approach, the team turned to spin: a magnetism-related property of electrons that points up or down and can be read, like electric charge can, as a 1 or 0. But random-access memory - the form that most computer applications rely on - requires a constant supply of power just to maintain those binary states. Applying voltage between the gate and source can dictate whether the electric current flows with low or high resistance, leading to either a buildup or absence of electron charges that gets encoded as a 1 or 0, respectively. Above that channel sits another terminal, the gate. Two of them, called the source and drain, serve as the starting and end points for electrons flowing through a circuit. Typical silicon-based transistors consist of multiple terminals. But above all, you need something that works differently than a silicon transistor, so that you can drop the power consumption, a lot.” ‘Now that it works, the fun begins’ “So you need something that you can shrink smaller, if possible. “We’re getting to the point where we’re going to approach the previous energy consumption of the United States just for memory (alone),” Dowben said. The microchip-enabled smartening of TVs, vehicles and other technology has only increased that demand. That predicament looms even as the demand for digital memory, and the energy needed to accommodate it, have soared amid the widespread adoption of computers, servers and the internet. And you generate heat with every device on an (integrated circuit), so you can’t any longer carry away enough heat to make everything work, either.” We’re basically down to the range where we’re talking about 25 or fewer silicon atoms wide. “There is a limit to how much smaller it can get. Dowben “The traditional integrated circuit is facing some serious problems,” said Dowben, Charles Bessey Professor of physics and astronomy at Nebraska.
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