  Samarium hexaboride (SmB6) has been presumed to show a topological Kondo
insulating state consisting of fully occupied quasiparticle bands in the
concept of a Fermi liquid. This gap emerging below a small coherence
temperature is the ultimate sign of coherence for a many-body system, which in
addition induces a non-trivial topology. Here, we demonstrate that just one
energy scale governs the gap formation in SmB6, which supports the Fermi liquid
description. The temperature dependence of the gap formation in the mixed
valence regime is captured within the dynamical mean field (DMFT) approximation
to the periodic Anderson model (PAM). The scaling property of the model with
the topological coherence temperature provides a strong connection to the
photoemission spectra of SmB6. Our results suggest a simple way to compare a
model study and an experiment result for heavy fermion insulators.
