Electron tunneling into intermediate-valence materials

Electron tunneling spectra of TmSe, SmS, SmB6, and CePd3 have been measured with the GaAs Schottky-barrier probe tunneling method. Antiferromagnetic TmSe shown an energy gap 2Δ (full width at half maximum) =1.2 meV, in situ pressure-transformed metallic SmS exhibits a gap of 1.7 meV, and SmB6 shows a gap of 2.7 meV, which is independent of magnetic field. For CePd3 an inelastic excitation is found near ± 14 meV, which is absent in YPd3. © 1982 The American Physical Society.