  We report directional point-contact spectroscopy data on the novel
Bi2Te3/Fe1+yTe interfacial superconductor for a Bi2Te3 thickness of 9 quintuple
layers, bonded by van der Waals epitaxy to a Fe1+yTe film at an atomically
sharp interface. Our data show a very large superconducting twin-gap structure
with an energy scale exceeding that of bulk FeSe or FeSe1-xTex by a factor of
4. While the larger gap is isotropic and attributed to a thin FeTe layer in
proximity of the interface, the smaller gap has a pronounced anisotropy and is
associated with proximity-induced superconductivity in the topological
insulator Bi2Te3. Zero resistance is lost above 8 K, but superconducting
fluctuations are visible up to at least 12 K and the large gap is replaced by a
pseudogap that persists up to 40 K. The spectra show a pronounced zero-bias
conductance peak in the superconducting state, which may be a signature of an
unconventional pairing mechanism.
