Possible quantum fluctuations in the vicinity of the quantum critical point of $(\mathbf{S}\mathbf{r},\mathbf{C}\mathbf{a}{)}_{\mathbf{3}}\mathbf{I}{\mathbf{r}}_{\mathbf{4}}\mathbf{S}{\mathbf{n}}_{\mathbf{13}}$ revealed by high-energy X-ray diffraction study

We explore the evolution of the structural phase transition of $\rm{(Sr, Ca)3Ir_4Sn{13}}$, a model system to study the interplay between structural quantum criticality and superconductivity, by means of high-energy x-ray diffraction measurements at high pressures and low temperatures. Our results confirm a rapid suppression of the superlattice transition temperature $T^{\ast }$ against pressure, which extrapolates to zero at a critical pressure of $\approx 1.79(4)$GPa\mathrm{.}ThetemperatureevolutionofthesuperlatticeBraggpeakin$\rm{Ca_3Ir_4Sn_{13}}$ reveals a drastic decrease of the intensity and an increase of the linewidth when $T\to 0$ K and $p\to p_c$. Such anomaly is likely associated to the emergence of quantum fluctuations that disrupt the formation of long-range superlattice modulation. The revisited temperature-pressure phase diagram of $(\mathrm{S}\mathrm{r},\mathrm{C}\mathrm{a}{)}_3\mathrm{I}{\mathrm{r}}_4\mathrm{S}{\mathrm{n}}_{13}$ thus highlights the intertwined nature of the distinct order parameters present in this system and demonstrates some similarities between this family and the unconventional superconductors.