Asoliton transistor
DOI: 10.1063/1.4797222
A three-terminal device based on Josephson junctions (sandwiches of two superconducting layers separated by a thin film of insulating material), and involving not the gated flow of electrons or holes but the controllable flow of tiny magnetic vortices, has been built and tested by Farshid Raissi, a scientist at the Toosi University of Technology in Tehran, Iran. In the 800-micron-long apparatus, trains of vortex solitons—created by applying small magnetic fields to the junction and set in motion by applying a brief current to the junction—are used to control the flow of a separate soliton train consisting of vortices established with a contrary magnetic orientation. Switching between on and off states is accomplished with the controlled annihilation of solitons and antisolitons. Raissi has observed switching speeds of 8 GHz, as fast as or faster than the best existing transistors, and he expects no insurmountable problems in shrinking and mass-producing his soliton device. He also expects to achieve speeds of 200 GHz, which would make this architecture quite attractive for use in supercomputers. (
