Topological current divider in a Chern insulator junction

Topological materials hold great promise for dissipationless information transmission. Here, the authors create Chern insulator junctions between domains with different Chern numbers in MnBi2Te4 to realize the basic operation of a topological circuit. A Chern insulator is a two-dimensional material that hosts chiral edge states produced by the combination of topology with time reversal symmetry breaking. Such edge states are perfect one-dimensional conductors, which may exist not only on sample edges, but on any boundary between two materials with distinct topological invariants (or Chern numbers). Engineering of such interfaces is highly desirable due to emerging opportunities of using topological edge states for energy-efficient information transmission. Here, we report a chiral edge-current divider based on Chern insulator junctions formed within the layered topological magnet MnBi2Te4. We find that in a device containing a boundary between regions of different thickness, topological domains with different Chern numbers can coexist. At the domain boundary, a Chern insulator junction forms, where we identify a chiral edge mode along the junction interface. We use this to construct topological circuits in which the chiral edge current can be split, rerouted, or switched off by controlling the Chern numbers of the individual domains. Our results demonstrate MnBi2Te4 as an emerging platform for topological circuits design.

Automated summary

The authors of this study have created Chern insulator junctions between domains with different Chern numbers in MnBi2Te4, enabling the basic operation of a topological circuit. By controlling the Chern numbers of the individual domains, the chiral edge current can be split, rerouted, or switched off, offering potential applications in energy-efficient information transmission.