Anisotropic optical response of Nb2SiTe4 under pressure

The optical response of a layered anisotropic crystal Nb2SiTe4 was investigated under varying pressure using synchrotron infrared spectroscopy, Raman spectroscopy, and first-principles calculation. This study revealed diverse trends in optical response and bandgap at different pressure levels. Below 5 GPa, the bandgap decreases rapidly due to the reduction of interlayer distance. The Raman and infrared optical response show significant changes at 11 and 21 GPa, suggesting structural and electronic structure transformation at these pressure points. Meanwhile, the optical responses exhibited distinct pressure effects along different crystal axes. Overall, these results provide valuable insights into the pressure-induced lattice deformation and optical transitions in Nb2SiTe4 and similar layered anisotropic materials, contributing to an insightful understanding of layered materials under pressure.