Ultrahigh-resolution and angle-resolved photoemission study of SmB6 Original Research Article

The photoemission spectra with the ultrahigh-energy resolution reveal the small gap formation at lower temperatures than the characteristic coherent temperature Tcoh. In addition, the temperature dependence of the density of states at Fermi level clearly shows a simple scaling relationship with Tcoh. The narrow 4f-band with a very small dispersion just below EF are observed by angle-resolved spectra at the first time.