Inspection of Tip-Induced Superconductivity in Topological Insulator Bi1.5Sb0.5Te1.7Se1.3
DOI:
https://doi.org/10.31305/rrijm.2026.v11.n06.021Keywords:
Strong spin-orbit coupling, 3D topological insulator, Dirac cones, Energy storageAbstract
Tip-induced superconductivity was found in a topological insulator Bismuth-Antimony-Tellurium-Selenium (Bi1.5Sb0.5Te1.7Se1.3) with a Tungsten (W) Normal Metal tip, where neither W nor Bi1.5Sb0.5Te1.7Se1.3 is a superconductor, but the contact of both shows superconducting nature. The superconductivity was confirmed by performing point-contact Andreev reflection spectroscopy in different regimes on a topological insulating material in a He4-based cryostat. In the conductance spectrum, the zero-bias peak confirms the superconducting nature of the point contact in the thermal regime, while the two dips at voltage values greater than the superconducting energy gap indicate the existence of critical current. In ballistic regime we found a zero-bias dip in conductance spectra which is direct evidence of superconducting energy gap open up at the fermi surface. The superconducting energy gap is indeed a hallmark of superconductivity. The superconducting critical temperature is found to be approximately 4.8 K from resistance temperature measurements. The critical temperature found out by temperature-dependent conductance spectra is similar to the R-T measurement and it observed 4.8 K. The upper critical magnetic field is found to be 2.6 Tesla by taking the variation of R-T measurement with magnetic field.
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