Search for superconducting proximity effect in a topological insulator and high temperature superconductor heterostructure Bi2Se3/Bi2Sr2CaCu2O8+

Abstract

Understanding the superconducting proximity effect on the surface of a topological insulator is of critical importance in realizing topological superconductivity and Majorana fermions in solid state settings. We fabricate delicate heterostructure samples between topological insulator (TI) Bi2Se3 thin film and high temperature superconductor Bi2Sr2CaCu2O8+ (Tc ~ 91 K). Using angle-resolved photoemission spectroscopy, we probe the electronic structure and the possible existence of superconducting gap on the top surface of Bi2Se3 thin films. Our systematic data show no significant proximity-induced superconducting gap in the topological surface states with sample temperature down to 10 K (<<91 K) and with a confidence level of sub 5 meV, much smaller than what have been claimed previously, which indicates the near absence of the proximity-induced superconductivity on the TI surface. Our momentum space imaging provides evidence for the coexistence of two crystalline phases in Bi2Se3/Bi2Sr2CaCu2O8+ samples, which we argue to be due to the strong mismatch of lattice crystalline symmetries. Our data identify the major contributors in reducing the proximity-induced superconducting gap below the meV range, including the lack of momentum space overlap between the Bi2Se3 and Bi2Sr2CaCu2O8+ Fermi surfaces, the strong mismatch of lattice crystalline symmetries and superconducting pairing symmetries, as well as the very short superconducting coherence length in Bi2Sr2CaCu2O8+. Our ARPES studies not only provide critical momentum space insights into the Bi2Se3/Bi2Sr2CaCu2O8+ heterostructure, but also set an upper bound on the proximity induced gap for realizing a Majorana fermion condition in this system, which may be further destabilized by the d-wave nodes dominated in a cuprate superconductor.

v2: 15 pages, 3 Figures (12 panels)

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• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Evidence of Majorana fermions in an Al - InAs nanowire topological superconductor
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• Proximity-induced high-temperature superconductivity in topological insulators Bi2Se3 and Bi2Te3
• Measuring the gap in ARPES experiments
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Cited by in corpus (10)

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• Competing energy scales in topological superconducting heterostructures
• Origin of Suppression of Proximity Induced Superconductivity in Bi/Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ Heterostructure
• Modeling Tunneling for the Unconventional Superconducting Proximity Effect
• Proximity effect in a heterostructure of a high $T_c$ superconductor with a topological insulator from Dynamical mean field theory
• Andreev Reflection without Fermi surface alignment in High T${}_c$-Topological heterostructures
• Proximity effect and inverse proximity effect in a topological-insulator/iron-based-superconductor heterostructure
• Angular momentum of vortex-core Majorana zero modes
• High Temperature Superconductivity Dominated by Inner Underdoped CuO${}_2$ Planes in Quadruple-Layer Cuprate (Cu,C)Ba${}_2$Ca${}_3$Cu${}_4$O${}_{11+\delta }$