Superconducting proximity effect in a topological insulator using Fe(Te,Se)

Abstract

Interest in the superconducting proximity effect has recently been reignited by theoretical predictions that it could be used to achieve topological superconductivity. Low-T${}_c$ superconductors have predominantly been used in this effort, but small energy scales of ~1 meV have hindered the characterization of the emergent electronic phase, limiting it to extremely low temperatures. In this work, we use molecular beam epitaxy to grow topological insulator Bi${}_2$Te${}_3$ in a range of thicknesses on top of a high-T${}_c$ superconductor Fe(Te,Se). Using scanning tunneling microscopy and spectroscopy, we detect Δ${}_{ind}$ as high as ~3.5 meV, which is the largest reported gap induced by proximity to an s-wave superconductor to-date. We find that Δ${}_{ind}$ decays with Bi${}_2$Te${}_3$ thickness, but remains finite even after the topological surface states had been formed. Finally, by imaging the scattering and interference of surface state electrons, we provide a microscopic visualization of the fully gaped Bi${}_2$Te${}_3$ surface state due to Cooper pairing. Our results establish Fe-based high-T${}_c$ superconductors as a promising new platform for realizing high-T${}_c$ topological superconductivity.

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Cited by in corpus (19)

• Majorana corner modes and tunable patterns in an altermagnet heterostructure
• Detection of second-order topological superconductors by Josephson junctions
• Hybrid symmetry epitaxy of superconducting Fe(Te,Se) film on a topological insulator
• Emergent vortex Majorana zero mode in iron-based superconductors
• Lattice distortion induced first and second order topological phase transition in rectangular high-T${}_{\mathrm{c}}$ superconducting monolayer
• High-temperature Majorana corner modes in a $d+i{d}^{\prime }$ superconductor heterostructure: Application to twisted bilayer cuprate superconductors
• Twofold symmetry of proximity-induced superconductivity in Bi${}_2$Te${}_3$/Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ heterostructures revealed by scanning tunneling microscopy
• Massive suppression of proximity pairing in topological (Bi${}_{1-x}$Sb${}_x{)}_2$Te${}_3$ films on niobium
• Observation of robust zero-energy state and enhanced superconducting gap in a tri-layer heterostructure of MnTe/Bi2Te3/Fe(Te, Se)
• Coulomb Blockade Effects in a Topological Insulator Grown on a High-Tc Cuprate Superconductor
• Rotational symmetry breaking and partial Majorana corner states in a high-Tc superconductor based heterostructure
• Stealth Majorana Zero Mode in a Trilayer Heterostructure MnTe/Bi2Te3/Fe(Te,Se)
• Detecting competing orders through the edge states in the heterostructures with high-Tc superconductors
• Superconductivity and vortex structure on Bi${}_2$Te${}_3$/FeTe${}_{0.55}$Se${}_{0.45}$ heterostructures with different thickness of Bi${}_2$Te${}_3$ films
• Proximity effect and inverse proximity effect in a topological-insulator/iron-based-superconductor heterostructure
• Interaction between spin and Abrikosov vortices in doped topological insulators
• Robust quantized thermal conductance of Majorana floating edge bands in d-wave superconductors
• Corner Flat Bands Induced by $d$-Density Wave and Partial Corner State Modification Due to Competition with $d$-Wave Superconductivity
• Proximity-Induced Superconductivity in a Topological Crystalline Insulator