Tunneling spectra of $\mathrm{TaO}_x$ junctions for van der Waals superconductors

TL;DR

This paper presents a high-quality tunneling spectroscopy platform using TaOx junctions for van der Waals superconductors, enabling detailed electronic structure analysis across various conditions.

Contribution

The authors develop a novel TaOx-based planar tunneling junction method that reproduces high-quality spectra comparable to ultra-high vacuum STM, suitable for diverse 2D materials.

Findings

Reproduces electronic signatures similar to STM measurements.

Allows high-precision spectroscopy over wide temperature and magnetic field ranges.

Provides a universal approach for probing 2D material electronic structures.

Abstract

Tunneling spectroscopy and its evolution are crucial for elucidating the intricate electronic structure and emergent phenomena in quantum materials.Nevertheless, high-quality measurements -- specifically those tracking evolution across temperature and external fields -- remain a formidable challenge. We have fabricated a high-quality $\mathrm{TaO}_x$-based planar tunneling junction by using magnetron sputtering for van der Waals (vdW) superconductors. Using the vdW superconductor $\mathrm{Bi}_2\mathrm{Sr}_2\mathrm{CaCu}_2\mathrm{O}_{8+\delta}$ (Bi2212) as a benchmark, this platform yields high-quality tunneling spectra, reproducing the electronic signatures obtained from scanning tunneling spectra acquired from atomically clean surfaces under ultra-high vacuum conditions. This architecture enables high-precision spectroscopy across extensive temperature and magnetic field ranges, offering a universal strategy for probing the electronic structures of diverse two-dimensional systems and facilitating future explorations of material properties.