Interfacially enhanced superconductivity in Fe(Te,Se)/Bi4Te3 heterostructures

Abstract

Realizing topological superconductivity by integrating high-transition-temperature ($T_C$) superconductors with topological insulators can open new paths for quantum computing applications. Here, we report a new approach for increasing the superconducting transition temperature ($T_C^{onset}$) by interfacing the unconventional superconductor Fe(Te,Se) with the topological insulator Bi-Te system in the low-Se doping regime, near where superconductivity vanishes in the bulk. The critical finding is that the $T_C^{onset}$ of Fe(Te,Se) increases from nominally non-superconducting to as high as 12.5 K when $B{i}_{2}T{e}_3$ is replaced with the topological phase $B{i}_{4}T{e}_3$. Interfacing Fe(Te,Se) with $B{i}_{4}T{e}_3$ is also found to be critical for stabilizing superconductivity in monolayer films where $T_C^{onset}$ can be as high as 6 K. Measurements of the electronic and crystalline structure of the $B{i}_{4}T{e}_3$ layer reveal that a large electron transfer, epitaxial strain, and novel chemical reduction processes are critical factors for the enhancement of superconductivity. This novel route for enhancing $T_C$ in an important epitaxial system provides new insight on the nature of interfacial superconductivity and a platform to identify and utilize new electronic phases.

18 pages, 5 figures, accepted by Advanced Materials

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Cited by in corpus (2)

• Interface-Enhanced Superconductivity in Ultrathin TiN Proximitized by Topological Insulators
• Unveiling In-Gap States and Majorana Zero Modes in Superconductor-Topological Insulator Bilayer model