Point-contact spectroscopy of Cu0.2Bi2Se3 single crystals

We report point-contact measurements in high-quality single crystals of Cu0.2Bi2Se3. We observe three different kinds of spectra: (1) Andreev-reflection spectra, from which we infer a superconducting gap size of 0.6 mV; (2) spectra with a large gap which closes above T-c at about 10 K; and (3) tunnelinglike spectra with zero-bias conductance peaks. These tunneling spectra show a very large gap of similar to 2 meV (2 Delta/KbTc similar to 14).