Transport spectroscopy of induced superconductivity in the three-dimensional topological insulator HgTe

Jonas Wiedenmann, Eva Liebhaber, Johannes Kübert, Erwann Bocquillon, Pablo Burset, Christopher Ames, Hartmut Buhmann, Teun M. Klapwijk, Laurens W. Molenkamp

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

The proximity-induced superconducting state in the three-dimensional topological insulator HgTe has been studied using electronic transport of a normal metal-superconducting point contact as a spectroscopic tool (Andreev point-contact spectroscopy). By analyzing the conductance as a function of voltage for various temperatures, magnetic fields, and gate voltages, we find evidence, in equilibrium, for an induced order parameter in HgTe of 70 μeV and a niobium order parameter of 1.1 meV. To understand the full conductance curve as a function of applied voltage we suggest a non-equilibrium-driven transformation of the quantum transport process where the relevant scattering region and equilibrium reservoirs change with voltage. This change implies that the spectroscopy probes the superconducting correlations at different positions in the sample, depending on the bias voltage.

Original languageEnglish
Article number165302
Number of pages8
JournalPhysical Review B (Condensed Matter and Materials Physics)
Volume96
Issue number16
DOIs
Publication statusPublished - 2017

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