Structural transition, metallization, and superconductivity in quasi-two-dimensional layered PdS2 under compression

Abstract

Based on first-principles simulations and calculations, we explore the evolutions of crystal structure, electronic structure and transport properties of quasi 2D layered PdS2 under compression by uniaxial stress and hydrostatic pressure. An interesting ferroelastic phase transition with lattice reorientation is revealed under uniaxial compressive stress, which originates from the bond reconstructions of the unusual PdS4 square-planar coordination. By contrast, the layered structure transforms to a 3D cubic pyrite-type structure under hydrostatic pressure. In contrary to the experimental proposed coexistence of layered PdS2-type structure with cubic pyrite-type structure at intermediate pressure range, we predict that the compression-induced intermediate phase showing the same structure symmetry with the ambient phase, except of sharply shrinking interlayer-distances. The coordination of the Pd ions not only plays crucial roles in the structural transition, but also lead to electronic structure and transport properties variations, which changes from square-planar to distorted octahedron in the intermediate phase, resulting in bandwidth broaden and orbital-selective metallization. In addition, the superconductivity in the cubic pyrite-type structure comes from the strong electron-phonon coupling in presence of topological nodal-line states. The strong interplay between structural transition, metallization and superconductivity in PdS2 provide a good platform to study the fundamental physics of the interactions between crystal structure and transport behavior, and the competition or cooperation between diverse phases.

Topological bands in the PdSe2 pentagonal monolayer

“…The band structure of monolayer PdSe 2 has been extensively studied in previous literature. 18,29–33,43 As indicated above, we have also carried out an extensive investigation of its electronic properties by employing several exchange–correlation functionals, detailed in Appendix A. We confirm the robustness of the nontrivial topology found for this material.…”

“…On the theoretical side, several works have analyzed the physical properties of the material in its monolayer and multilayer forms. 29–33 Among these theoretical accounts the band connectivity and the symmetry-related properties of the electronic structure have not been studied in detail for monolayer PdSe 2 ; we address this issue in this work. Using the theory of symmetry indicators along with first-principles calculations, we identify that the lowest conduction bands of monolayer PdSe 2 realize a topologically nontrivial phase.…”

Site-specific symmetry sensitivity of angle-resolved photoemission spectroscopy in layered palladium diselenide

“…Here, we employ a simple colour-coded approach: the k-resolved density of states of the CB, in agreement with our own calculations (Fig. 4b) and other recent work [47].…”

Topological bands in monolayer PdSe$_2$

“…Also, good electrical transport [10], optical [11][12][13][14] and thermoelectric properties [15] have been experimentally reported. On the theoretical side, several works have analyzed the physical properties of the material in its monolayer and multilayer form [16][17][18][19][20]. Among these theoretical accounts the band connectivity and the symmetry-related properties of the electronic structure has not been studied in detail for monolayer PdSe 2 ; we address this issue in this work.…”

“…Electronic band structure and symmetry indicators -The band structure of monolayer PdSe 2 has been extensively studied in previous works [5,[16][17][18][19][20]. Here we focus on the band connectivity an associated topological properties of the low energy bands around the Fermi level.…”