  Stars that are tidally disrupted by the massive black hole (MBH) may
contribute significantly to the growth of the MBH, especially in dense nuclear
star clusters (NSCs). Yet, this tidal disruption accretion (TDA) of stars onto
the MBH has largely been overlooked compared to the gas accretion (GA) channel
in most numerical experiments until now. In this work, we implement a black
hole growth channel via TDA in the high-resolution adaptive mesh refinement
code Enzo to investigate its influence on a MBH seed's early evolution. We find
that a MBH seed grows rapidly from $10^3\,\mathrm{M}_\odot$ to $\gtrsim
10^6\,\mathrm{M}_\odot$ in 200\,Myrs in some of the tested simulations.
Compared to a MBH seed that grows only via GA, TDA can enhance the MBH's growth
rate by up to more than an order of magnitude. However, as predicted, TDA
mainly helps the early growth of the MBH (from $10^{3-4}\,\mathrm{M}_\odot$ to
$\lesssim10^{5}\,\mathrm{M}_\odot$) while the later evolution is generally
dominated by GA. We also observe that the star formation near the MBH is
suppressed when TDA is most active, sometimes with a visible cavity in gas (of
size $\sim$ a few pc) created in the vicinity of the MBH. It is because the MBH
may grow expeditiously with both GA and TDA, and the massive MBH could consume
its neighboring gas faster than being replenished by gas inflows. Our study
demonstrates the need to consider different channels of black hole accretion
that may provide clues for the existence of supermassive black holes at high
redshifts.
