  We introduce a possible disruption mechanism of dust grains in planet
formation by their spinning motion. This mechanism has been discussed as
rotational disruption for the interstellar dust grains. We theoretically
calculate whether porous dust aggregates can be disrupted by their spinning
motion and if it prohibits dust growth in protoplanetary disks. We assume
radiative torque and gas-flow torque as driving sources of the spinning motion,
assume that dust aggregates reach a steady-state rigid rotation, and compare
the obtained tensile stress due to the centrifugal force with their tensile
strength. We model the irregularly-shaped dust aggregates by introducing a
parameter, $\gamma_\mathrm{ft}$, that mimics the conversion efficiency from
force to torque. As a result, we find that porous dust aggregates are
rotationally disrupted by their spinning motion induced by gas flow when their
mass is larger than $\sim10^8$ g and their volume filling factor is smaller
than $\sim 0.01$ in our fiducial model, while relatively compact dust
aggregates with volume filling factor more than 0.01 do not face this problem.
If we assume the dust porosity evolution, we find that dust aggregates whose
Stokes number is $\sim0.1$ can be rotationally disrupted in their growth and
compression process. Our results suggest that the growth of dust aggregates may
be halted due to rotational disruption or that other compression mechanisms are
needed to avoid it. We also note that dust aggregates are not rotationally
disrupted when $\gamma_\mathrm{ft}\leq0.02$ in our fiducial model and the
modeling of irregularly-shaped dust aggregates is essential in future work.
