We report high-pressure Raman scattering measurements on the tetragonal phase of InTe corroborated with the first-principles density functional theory and synchrotron x-ray diffraction measurements. Anomalous pressure-dependent linewidths of the $A_{1\mathrm{g}}$ and $E_{\mathrm{g}}$ phonon modes provide evidence of an isostructural electronic transition at $\sim 3.6\mathrm{GPa}$. The first-principles theoretical analysis reveals that it is associated with a semiconductor-to-metal transition due to increased density of states near the Fermi level. Further, this pressure induced metallization acts as a precursor for structural phase transition to a face centered cubic phase ($Fm\overline{3}m$) at $\sim 6.0\mathrm{GPa}$. Interestingly, theoretical results reveal a pressure induced band inversion at the $Z$ and $M$ points of the Brillouin zone corresponding to pressures $\sim 1.0$ and $\sim 1.4\mathrm{GPa}$, respectively. As the parity of bands undergoing inversions is the same, the topology of the electronic state remains unchanged, and hence InTe retains its trivial band topology $({\mathbb{Z}}_2=0)$. The pressure dependent behavior of the $A_{1\mathrm{g}}$ and $E_{\mathrm{g}}$ modes can be understood based on the results from the synchrotron x-ray diffraction, which shows anisotropic compressibility of the lattice in the $a$ and $c$ directions. Our Raman measurements up to $\sim 19\mathrm{GPa}$ further confirms the pressure induced structural phase transition from a face-centered to primitive cubic ($Fm\overline{3}m$ to $Pm\overline{3}m$) at $P\sim 15\mathrm{GPa}$.

• Received 5 November 2017
• Revised 16 April 2018

DOI:https://doi.org/10.1103/PhysRevB.97.155158