TOPOLOGICAL PHASE TRANSITION IN THREE DIMENSIONAL MATERIALS

Abstract

In the present work, our first-principles study shows the topological phase transition in rare-earth monopnictides GdSb and ternary chalcogenide SnPbSe2 under the influence of hydrostatic pressure and biaxial strain. The dynamical and thermodynamical stabilities of materials are verified with the applied hydrostatic pressure and biaxial strain. The structural, electronic, and topological properties are studied using the density functional theory with hybrid functionals. The topological nature has been verified by calculating Z2 topological invariants and surface density of states (SDOS). At ambient conditions, both materials show a topological trivial nature, which has been verified by the energy band gap in the bulk band structure and (0;000) values of Z2 topological invariants. The topological phase transition in GdSb and SnPbSe2 is obtained at 6 GPa of hydrostatic pressure and 2% of biaxial strain respectively. The occurrence of inverted contribution of orbitals in band inversions near the Fermi level are observed. The non zero value of first Z2 topological invariant and presence of Dirac cone in the surface state has verified the non-trivial topological nature of materials. However, when we further increase the hydrostatic pressure and biaxial strain in these materials, respectively, another band inversion in bulk band structure is also observed. The calculation of Z2 topological invariants is (0;000) and has verified the trivial nature of materials after even number of band inversions.