A twisted pole, and a tiny trick with current
Two porters step onto a narrow footbridge laid over a rubbery mat, a long pole on their shoulders. If their feet land together, the pole stays straight and slides through the slot at the far end. If one side creeps ahead, the pole slowly twists. A tiny mismatch can grow into a big miss.
That is the trick in this device. The current runs only along the skin of a special material, not through its middle. Instead of pulling directly on the moving charges, a voltage presses on a layer underneath, which stretches the surface path above. Thin barrier layers at each end help launch and read the spin more cleanly.
A spin starts at one end pointing one way, like the pole leaving level. On the surface path it splits into two linked motions, like two walkers carrying the same pole with slightly different natural strides. Stretch the layer underneath, and those two motions speed up by different amounts, so the twist by the far end changes.
The exit slot is the magnetic contact at the far end. When the two parts meet again, the spin has turned a bit, and that contact lets more or less current through depending on its final angle. So the mapping is simple: walkers are the two motions, the stretchable mat is the strained layer, and the slot is the drain. Change the stretch, change the current.
There is a snag. The current does wobble up and down, but not by much. Even in the best case here, the gap between high and low stays small, so it is a poor on off switch. The fresh idea works, but it does not cure the old weakness of spin transistors for plain digital logic.
But the wobble becomes handy when the job changes. As the gate rises and falls, the current can pass several peaks in one swing, like the pole lining up with the slot more than once while the mat stretches and relaxes. In one example, a single input cycle produces four output ripples while using very little energy.
So the surprise is not a better switch. It is a neat signal shaper. Squeezing the surface of this special material may be too gentle to give a firm yes or no, yet it can still turn one smooth swing into several smaller beats. The twisted pole misses the slot as a gatekeeper, but earns its keep as a rhythm maker.