  $\alpha$-RuCl$_3$ has been hinted as a spin-orbital-assisted Mott insulator
in proximity to a Kitaev spin liquid state. Here we present ARPES measurements
on single crystal $\alpha$-RuCl$_3$ in both the pristine and electron-doped
states, and combine them with LDA+SOC+U calculations performed for the several
low-energy competing magnetically ordered states as well as the paramagnetic
state. A large Mott gap is found in the measured band structure of the pristine
compound that persists to more than 20 times beyond the magnetic ordering
temperature, though the paramagnetic calculation shows almost no gap. Upon
electron doping, spectral weight is transferred into the gap but the new states
still maintain a sizable gap from the Fermi edge. These findings are most
consistent with a Mott insulator with a somewhat exotic evolution out of the
Mott state with both temperature and doping, likely related to unusually strong
spin fluctuations.
