Broad and colossal edge supercurrent in a topological semimetal Cd₃As₂ Josephson junction

One-dimensional supercurrent has attracted great interest due to its potential to manipulate topological superconducting states [1]. Apart from superconducting nanowires, proximity-induced boundary superconductivity has been realized in quantum (spin) Hall edge states, as well as in higher-order topological hinge states. Recent theories predict that the non-Hermitian skin effect, the aggregation of non-Bloch eigenstates at open boundaries, promises an abnormal edge channel [2,3].

Here we report the observation of broad edge supercurrent in Dirac semimetal Cd₃As₂ Josephson junctions [4]. The as-grown Cd₃As₂ nanoplates are electron-doped by intrinsic defects, resulting in a finite quasiparticle lifetime that enhances the non-Hermitian perturbations. The superconducting quantum interference indicates edge supercurrent with a width of ~1.6 μm and a magnitude of ~1 μA at 10 mK. The wide and large edge supercurrent is inaccessible for a conventional edge system and suggests the presence of the non-Hermitian skin effect. A supercurrent nonlocality is further observed, indicating the topological nature of the boundary states. The interplay between band topology and non-Hermiticity is beneficial for exploiting exotic topological matter.

[1] J. Alicea, Y. Oreg, G. Refael, F. von Oppen, and M. P. A. Fisher, Nat. Phys. 7, 412 (2011).

[2] S. Yao and Z. Wang, Phys. Rev. Lett. 121, 086803 (2018).

[3] K. Zhang, Z. Yang, and C. Fang, Nat. Commun. 13, 2496 (2022).

[4] C. G. Chu et al., Nat. Commun. 14, 6162 (2023).