The first-principles study of LaSe and LaTe in B1 and B2 structures

The structural, electronic and dynamical properties of LaSe and LaTe compounds in NaCl(B1) and CsCl(B2) structures are studied by performing ab initio calculations within the generalized gradient approximation (GGA). Bulk properties including lattice constants, static bulk modulus, first-order pressure derivative of the bulk modulus, cohesive energies and first-order phase transitions are reported and compared with available experimental and other theoretical results. The electronic band structure is also presented for these materials. For the first time, the electronic structure results are used, within the implementation of linear-response technique, for calculations of phonon properties. A detailed discussion of atomic displacement pattern for LaTe in B1 structure is also presented. The phonon dispersion curves for two materials are compared and contrasted.