Tailoring Superconductivity in Large-Area Single-Layer NbSe2 via Self-Assembled Molecular Adlayers

TL;DR

This study demonstrates how self-assembled molecular adlayers can be used to tune the superconducting critical temperature of large-area NbSe2 monolayers by creating electrostatic fields, offering a new approach for designing functional 2D materials.

Contribution

The paper introduces a method to control superconductivity in NbSe2 monolayers using molecular adlayers, a novel surface engineering technique for 2D materials.

Findings

Molecular dipoles act as fixed gate terminals influencing Tc.

Electric field polarity controls increase or decrease in Tc.

Functionalization enhances air stability and scalability.

Abstract

Two-dimensional transition metal dichalcogenides (TMDs) represent an ideal testbench for the search of materials by design, because their optoelectronic properties can be manipulated through surface engineering and molecular functionalization. However, the impact of molecules on intrinsic physical properties of TMDs, such as superconductivity, remains largely unexplored. In this work, the critical temperature (TC) of large-area NbSe2 monolayers is manipulated, employing ultrathin molecular adlayers. Spectroscopic evidence indicates that aligned molecular dipoles within the self-assembled layers act as a fixed gate terminal, collectively generating a macroscopic electrostatic field on NbSe2. This results in an \sim 55\% increase and a 70\% decrease in TC depending on the electric field polarity, which is controlled via molecular selection. The reported functionalization, which improves the air stability of NbSe2, is efficient, practical, up-scalable, and suited to functionalize large-area TMDs. Our results indicate the potential of hybrid 2D materials as a novel platform for tunable superconductivity.