Intrinsic surface p-wave superconductivity in layered AuSn₄

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Topological superconductivity (TSC) is sought for Majorana modes, but fabricating TSC heterostructures and intrinsic TSC materials faces challenges.
• Existing methods for achieving TSC are limited by material constraints, disorder sensitivity, and topological restrictions.

Purpose of the Study:

• To report a new type of intrinsic topological superconductivity (IS-TSC) in layered materials.
• To demonstrate IS-TSC in AuSn4 and investigate its properties for potential applications in topological quantum computing.

Main Methods:

• Synthesized layered AuSn4 and characterized its superconducting properties.
• Utilized magneto-transport measurements and point-contact spectroscopy (PCS) to probe superconductivity.
• Performed first-principles calculations to understand the electronic structure and pairing mechanism.

Main Results:

• AuSn4 exhibits intrinsic surface topological superconductivity (IS-TSC) with a critical temperature (Tc) of 2.4 K.
• Two-dimensional (2D) superconductivity was confirmed by distinct in-plane and out-of-plane upper critical fields.
• Two-fold symmetric angular dependencies in magneto-transport and zero-bias conductance peaks (ZBCP) indicate unconventional pairing symmetry.
• Superconducting gap and surface multi-bands with Rashba splitting were observed, suggesting a mix of p-wave surface and s-wave bulk contributions.

Conclusions:

• Layered AuSn4 is a novel material exhibiting intrinsic surface topological superconductivity (IS-TSC).
• The observed 2D unconventional superconductivity arises from the interplay of surface and bulk contributions, influenced by the Rashba effect.
• AuSn4 presents a promising new paradigm for realizing topological superconductivity (TSC) and exploring Majorana modes in layered materials.