Tunable Two-Dimensional Group-III Metal Alloys

TL;DR

This paper demonstrates the controllable tuning of electronic, optical, and superconducting properties of air-stable 2D metal alloys through compositional adjustments, enabling customizable nanoscale quantum devices.

Contribution

It introduces a novel synthesis method for large-area, composition-tunable 2D metal alloys with no phase segregation, expanding the design space for quantum materials.

Findings

Alloys exhibit near-complete solid solubility without phase segregation.

Optical and electronic properties vary predictably with alloy composition.

Superconductivity and charge transfer are controllably tuned by alloy ratio.

Abstract

Chemically stable quantum-confined 2D metals are of interest in next-generation nanoscale quantum devices. Bottom-up design and synthesis of such metals could enable the creation of materials with tailored, on-demand, electronic and optical properties for applications that utilize tunable plasmonic coupling, optical non-linearity, epsilon-near-zero behavior, or wavelength-specific light trapping. In this work, we demonstrate that the electronic, superconducting and optical properties of air-stable two-dimensional metals can be controllably tuned by the formation of alloys. Environmentally robust large-area two-dimensional InxGa1-x alloys are synthesized by Confinement Heteroepitaxy (CHet). Near-complete solid solubility is achieved with no evidence of phase segregation, and the composition is tunable over the full range of x by changing the relative elemental composition of the precursor. The optical and electronic properties directly correlate with alloy composition, wherein the dielectric function, band structure, superconductivity, and charge transfer from the metal to graphene are all controlled by the indium/gallium ratio in the 2D metal layer.