A group of scientists lead by Dragan Mihailović, prof. dr., from the Complex Matter F7 at the Jožef Stefan Institute (IJS) in Ljubljana achieved a double breakthrough - they discovered a new type of computer memory element with a record speed, and they were the first ones to do so!
In their paper, published in Nature Communications, they demonstrate fast resistance switching between Mott insulator and metallic states in the charge density wave system 1T-TaS2 caused by pulsed current injection.
Instead of, for example, switching magnetic or ferroelectric order, the researchers explored switching between metallic and insulating phases by the motion of ions. Their speed is, however, limited by slow nucleation and inhomogeneous percolative growth.
As published in the paper, they discovered that when "a charge pulse travels through the material, it converts a commensurately ordered polaronic Mott insulating state in 1T–TaS2 to a metastable electronic state with textured domain walls, accompanied with a conversion of polarons to band states, and concurrent rapid switching from an insulator to a metal. The large resistance change, high switching speed (30 ps) and ultralow energy per bit opens the way to new concepts in non-volatile memory devices manipulating all-electronic states."