Anomalous Superconductivity in Twisted MoTe2 Nanojunctions

TL;DR

This paper demonstrates the creation of anomalous superconducting junctions in twisted bilayer MoTe2, revealing unexpected behaviors and potential for new quantum states in moire materials.

Contribution

It introduces a novel on-chip growth method for superconducting junctions in moire materials and uncovers anomalous superconducting effects in twisted MoTe2 junctions.

Findings

Enhanced superconductivity in junctions compared to adjacent regions.

Observation of a V-shaped minimum in critical current at zero magnetic field.

Unusual magnetic field response suggesting mixed parity superconductivity.

Abstract

Introducing superconductivity in topological materials can lead to innovative electronic phases and device functionalities. Here, we present a new strategy for quantum engineering of superconducting junctions in moire materials through direct, on-chip, and fully encapsulated 2D crystal growth. We achieve robust and designable superconductivity in Pd-metalized twisted bilayer molybdenum ditelluride (MoTe2) and observe anomalous superconducting effects in high-quality junctions across ~ 20 moire cells. Surprisingly, the junction develops enhanced, instead of weakened, superconducting behaviors, exhibiting fluctuations to a higher critical magnetic field compared to its adjacent Pd7MoTe2 superconductor. Additionally, the critical current further exhibits a striking V-shaped minimum at zero magnetic field. These features are unexpected in conventional Josephson junctions and indeed absent in junctions of natural bilayer MoTe2 created using the same approach. We discuss implications of these observations, including the possible formation of mixed even- and odd-parity superconductivity at the moire junctions. Our results also demonstrate a pathway to engineer and investigate superconductivity in fractional Chern insulators.