Proximity-Induced Unconventional Superconducting Quantum Oscillation in WTe2/NbSe2 Heterostructures

Abstract

The electron pairing mechanisms in topological superconductors are pivotal for understanding the emergent topology-related quantum states and play key roles in condensed matter physics. Theoretically, the quantization of magnetic flux in nano-hole arrays within topological superconductors can be studied for understanding the Bogoliubov quasiparticles via the Little–Parks oscillation. However, experimental evidence of the quasiparticle states in such structures of topological superconductors remains elusive. Here, the unconventional superconducting quantum oscillation phenomena of the proximity-induced 2D topological superconductivity (TSC) is demonstrated in a nano-hole array of WTe2/NbSe2 heterojunction. The unconventional oscillation period in WTe2 is substantially smaller than that in the s-wave superconductor NbSe2 (corresponds to Cooper pairs), implying the probable presence of novel quasiparticle states associated with TSC. Interestingly, such phenomena of multi-charge flux quanta might be related to the multi-particle bound states of TSC. These observations provide a new approach for exploring the unconventional superconducting quantum states in topological superconductors.