  The multipole modes of excitation for tetrahedrally deformed neutron-rich Zr
isotopes are investigated using the quasiparticle finite amplitude method based
on the covariant density functional theories. By employing the
density-dependent point-coupling covariant density functional theory with the
parameter set DD-PC1 in the particle-hole channel and a separable pairing
interaction of finite range, it is observed that a distinct peak emerges at
$\omega = 9.0 - 10.0$ MeV in the isoscalar quadrupole $K=0$ strength when
$\beta_{32}$ distortion is considered for $^{110,112}$Zr. This peak is absent
when the deformation is limited to axially symmetric octuple or spherical case.
It also does not appears in neighboring axially quadrople or octupole deformed
nuclei, thus can be viewed as an indicator for the tetrahedral shape.
