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

Abstract

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 ∼ 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 (Fm3‾m) at ∼ 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 ∼ 1.0 and ∼ 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 (ℤ₂ = 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 ∼19 GPa further confirms the pressure induced structural phase transition from a face-centered to primitive cubic (Fm3‾m to Pm3‾m) at P∼15 GPa.