  Accretion on to seed black holes (BHs) is believed to play a crucial role in
formation of supermassive BHs observed at high-redshift (z>6). Here, we
investigate the combined effect of gas angular momentum and radiation feedback
on the accretion flow, by performing 2D axially symmetric radiation
hydrodynamics simulations that solve the flow structure across the Bondi radius
and the outer part of the accretion disc simultaneously. The accreting gas with
finite angular momentum forms a rotationally-supported disc inside the Bondi
radius, where the accretion proceeds by the angular momentum transport due to
assumed alpha-type viscosity. We find that the interplay of radiation and
angular momentum significantly suppresses accretion even if the radiative
feedback is weakened in an equatorial shadowing region. The accretion rate is
O(alpha)\sim O(0.01-0.1) times the Bondi value, where alpha is the viscosity
parameter. By developing an analytical model, we show that such a great
reduction of the accretion rate persists unless the angular momentum is so
small that the corresponding centrifugal radius is \lesssim 0.04 times the
Bondi radius. We argue that BHs are hard to grow quickly via rapid mass
accretion considering the angular momentum barrier presented in this paper.
