Pressure induced band inversion, electronic and structural phase transitions in InTe: A combined experimental and theoretical study

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(1g) and E-g phonon modes provide evidence of an isostructural electronic transition at similar to 3.6 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 (3) over barm) at similar to 6.0 GPa. Interestingly, theoretical results reveal a pressure induced band inversion at the Z and M points of the Brillouin zone corresponding to pressures similar to 1.0 and similar to 1.4 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 (Z(2) = 0). The pressure dependent behavior of the A(1g) and E-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 similar to 19 GPa further confirms the pressure induced structural phase transition from a face-centered to primitive cubic (Fm (3) over barm to Pm (3) over barm) at P similar to 15 GPa.