Manipulating Individual Topological Solitons and Bisolitons in an Electronic System

While localized topological modes in quantum materials, such as topological solitons and Majorana fermions, promise loss-less delivery of classical and quantum information, manipulating individual topological modes has been highly challenging. The manipulation of Z₄ topological solitons is reported in a 1D charge density wave (CDW) insulator of indium atomic wires on a silicon surface. Using the current injection from a scanning tunneling microscopy tip, individual defects-pinned solitons can be created, translated, and annihilated. Moreover, this method is applied to induce bi-soliton processes such as transforming a soliton into a different soliton, fissioning one into two solitons, and fusing and dissociating two solitons, where soliton topological charges are manipulated. The theoretical calculations attribute the mechanism of manipulation to local destabilization of the CDW structure by hole doping. This work demonstrates addressable control over most of the possible operations between individual and paired Z₄ solitons and secures a way to investigating dynamics of quantum solitons and to processing topologically-protected multi-valued information in electronic systems.