  Tb2Ti2O7, a pyrochlore system, has garnered significant interest due to its
intriguing structural and physical properties and their dependence on external
physical parameters. In this study, utilizing high-brilliance synchrotron X-ray
diffraction, we conducted a comprehensive investigation of structural evolution
of Tb2Ti2O7 under external pressure and temperature. We have conclusively
confirmed the occurrence of an isostructural phase transition beyond the
pressure of 10 GPa. The transition exhibits a distinct signature in the
variation of lattice parameters under pressure and leads to changes in
mechanical properties. The underlying physics driving this transition can be
understood in terms of localized rearrangement of atoms while retaining the
overall cubic symmetry of the crystal. Notably, the observed transition remains
almost independent of temperature. Our findings provide insights into the
distinctive behaviour of the isostructural phase transition in Tb2Ti2O7.
