Fig. 2
a STS spectra on bare NbSe2 and 1 QL to 11 QL Bi2Te3 surfaces, measured at 400 mK). b Exponential fit of the gap sizes extracted from a by the positions of the coherence peaks. c ARPES measurement of 4 QL Bi2Se3/NbSe2 heterostructure at 12 K. d Symmetrized ARPES spectra at ±k1, ±k2, and ±k3 in c at T∼1 K. a and b reprinted with permission from ref. 15, copyright 2014 by the American Physical Society, a and b Reprinted by permission from Macmillan Publishers Ltd: Nature Physics, ref. 30, copyright 2014
