  We compute the low-energy excitation spectrum and the dynamical spin
structure factor of the Kitaev-Heisenberg-Gamma model through a variational
approach based on the exact fractionalized excitations of the pure Kitaev
honeycomb model. This novel approach reveals the physical reason for the
asymmetric stability of the Kitaev spin liquid phases around the ferromagnetic
and antiferromagnetic Kitaev limits. Moreover, we demonstrate that the
fractionalized excitations form bound states in specific regions of each Kitaev
spin liquid phase and that certain phase transitions induced by Heisenberg and
Gamma interactions are driven by the condensation of such a bound state.
Remarkably, this bound state appears as a sharp mode in the dynamical spin
structure factor, while its condensation patterns at the appropriate phase
transitions provide a simple explanation for the magnetically ordered phases
surrounding each Kitaev spin liquid phase.
