Scientists twist tiny crystals to control electricity

Scientists at the RIKEN Center for Emergent Matter Science, along with collaborators, have developed a technique for building three dimensional nanoscale devices directly from single crystal materials. The method uses a focused ion beam instrument that removes material at extremely small scales. The researchers carved tiny helical structures from a topological magnetic crystal made of cobalt, tin and sulfur. Tests showed that these structures behave like switchable diodes, with electric current traveling more easily in one direction than the other. The effect can be flipped According to Max Birch, the first Yoshinori Tokura, who leads the research group, said the approach enables device designs that combine topological or strongly correlated electronic states with engineered curvature in the ballistic or hydrodynamic transport regime.