Figure 1

(Color online) Schematic representation of the proposed experimental setup. The quantum spin Hall phase is realized in an inverted and insulating HgTe/CdTe quantum well. Transport along the one-dimensional edge of the QSH phase is measured by a standard two-terminal setup with normal electrodes. Between these two electrodes, a superconducting electrode is deposited over a length $l$ on one side of the sample.Reuse & Permissions

Figure 2

Scattering processes. With Fermi-liquid leads, an incident electron (1) can be backscattered as an electron (2), reflected as a hole (local Andreev reflection) (3), transmitted as an electron (4) or transmitted as a hole (nonlocal Andreev process) (5). In the QSH edge state, helicity conservation prevents electronic backscattering (2) and hole transmission (5). Furthermore, at low energy and for a wide superconductor, electron transmission (4) vanishes and only Andreev reflection (3) remains.Reuse & Permissions

Figure 3

(Color online) Plot of $T_{ϵ}$ for a rectangular gap function $\Delta \left(x\right)=\Delta \theta \left(x\right)\theta \left(l-x\right)$: the horizontal axis display $l/\xi$ and $ϵ/\left|\Delta \right|$. For $l\gtrsim \xi$, the transmission vanishes for subgap electrons $ϵ\le \left|\Delta \right|$. Oscillations of the transmission coefficient for $ϵ\ge \left|\Delta \right|$ can be interpreted as Fabry-Perot resonances of the Bogoliubov excitations through the superconducting barrier.Reuse & Permissions

Figure 4

(Color online) The noise response $\partial S_S/\partial \mu$ in units of $e^2/h$ (solid line) is maximal around $l\sim \xi$. The Fano factor $F=S_S/2e⟨I_S⟩$ (dashed line) as a function of $l/\xi$.Reuse & Permissions