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Abstract

The design of advanced functionality in superconducting devices usually focuses on materials engineering, either in heterostructures or in compounds of unconventional quantum materials. Here we demonstrate a different strategy to bespoke behavior by controlling the 3D shape of superconductors on the micron-scale. As a demonstration, a large superconducting diode effect is engineered solely by 3D shape design of a conventional superconductor, ion-beam deposited tungsten. Its highly efficient diode behavior appears from its triangular cross-section when vortices break time-reversal and all mirror symmetries. Yet reciprocity is observed at special field angles where the lack of symmetry would lead one to expect diode behavior. This can be understood as a topological mechanism that is robust against deformations of the triangle. Geometry and topology induce a rich internal structure due to the high-dimensional tuning parameter space of 3D structures, inaccessible to the conventional 2D design strategies in thin films.