Robust two-dimensional superconductivity and vortex system in Bi(2)Te(3)/FeTe heterostructures

The discovery of two-dimensional superconductivity in Bi(2)Te(3)/FeTe heterostructures provides a new platform for the search of Majorana fermions in condensed matter systems. Since Majorana fermions are expected to reside at the core of the vortices, a close examination of the vortex dynamics in superconducting interface is of paramount importance. Here, we report the robustness of the interfacial superconductivity and 2D vortex dynamics in four as-grown and aged Bi(2)Te(3)/FeTe heterostructure with different Bi(2)Te(3) epilayer thickness (3, 5, 7, 14 nm). After two years’ air exposure, superconductivity remains robust even when the thickness of Bi(2)Te(3) epilayer is down to 3 nm. Meanwhile, a new feature at ~13 K is induced in the aged samples, and the high field studies reveal its relevance to superconductivity. The resistance of all as-grown and aged heterostructures, just below the superconducting transition temperature follows the Arrhenius relation, indicating the thermally activated flux flow behavior at the interface of Bi(2)Te(3) and FeTe. Moreover, the activation energy exhibits a logarithmic dependence on the magnetic field, providing a compelling evidence for the 2D vortex dynamics in this novel system. The weak disorder associated with aging-induced Te vacancies is possibly responsible for these observed phenomena.