| While there is much interest in superconductor-topological insulator hybrid structures the fact that many available topological insulators are "topological metals" has been overlooked. On the other hand superconducting proximity effect in topological metal can present new opportunities. Here we numerically study proximity induced pair amplitudes for different channels in s-wave superconductor superconductor-topological metal slab hybrid structure by self-consistently solving Bogoliubov-deGenne equations. We find three regimes depending on chemical potential: topological insulator, helical topological metal with spin-momentum locking, topological metal without spin-momentum locking. We then study the vortex bound state spectra in these three regimes and find the majorana zero mode bound to the naked surface clear energy separation from the bulk bound states, only in the helical topological metal regime. Such bound state in the naked surface will be directly accessible to surface probes for both detection and manipulation. |
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