Suppression of dissipation in superconducting nanostrips by parallel magnetic field*

Common wisdom dictates that an increase in the magnetic field escalates the loss of energy since the number of vortices increases. Here we show that this is no longer true if the magnetic field and the current are applied parallel to each other. Experimental studies on superconducting MoGe nanostrips reveal that the initial dissipative state with increasing magnetic field is followed by a pronounced resistance drop, signifying a reentrance of the superconducting state. Large-scale simulations of the 3D time-dependent Ginzburg–Landau model indicate that the intermediate resistive state is due to an unwinding of twisted vortices. When the magnetic field increases, this instability is suppressed due to a better accommodation of the vortex lattice to the pinning configuration. Our findings show that magnetic field and geometrical confinement can suppress the dissipation induced by vortex motion. [PNAS 114, E10274 (2017)]