Experimental and Theoretical Investigation on the Relative Stability of the PdS<sub>2</sub>‐ and Pyrite‐Type Structures of PdSe<sub>2</sub>.

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.

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“…1). [4][5][6]26] Raman spectra suggest that the PdS2-type and pyrite-type phases coexist in the intermediate pressure range. [4][5][6] Fig.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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“…1. Experimental lattice constants are a = 5.7457, b = 5.8678, and c = 7.6946 Å [23], and in our work the lattice vectors a, b, and c are along the x, y, and z axes, respectively. We construct atomic structures of monolayer and bilayer PdSe 2 by cutting the bulk atomic structure and including a large enough vacuum region of about 20 Å.…”

Section: A Atomic Structuresmentioning

confidence: 83%

“…1(a), where triple layers are separated by 2.40 Å. Atomic positions are from experimental values [23]; that is, one of the Pd atoms is at (0, 0, 0), and one of the Se atoms is at (0.11125, 0.11799, 0.40573) in terms of fractional coordinates with respect to lattice vectors, and other atomic positions are determined by symmetries.…”

Section: A Atomic Structuresmentioning

confidence: 99%

Quasiparticle band structures of bulk and few-layer PdSe2 from first-principles GW calculations

Kim,

Choi

2021

Preprint

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We performed first-principles density functional theory (DFT) and GW calculations to investigate electronic structures of bulk and few-layer PdSe2. We obtained the quasiparticle band structure of bulk PdSe2, and the obtained energy gap agrees excellently with the reported experimental value. For monolayer and bilayer PdSe2, we obtained quasiparticle band structures with respect to the vacuum level. We analyzed DFT and GW band structures in detail, finding k-space positions of valence band maxima and conduction band minima, effective masses, the quasiparticle density of states, work functions, ionization potentials, electron affinities, and k-space shapes of electron and hole pockets. These results provide a foundation for development of basic studies and device applications.

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“…Many previous studies have shown that one can tune the electronic and optical properties of the TMDs by applying mechanical strains [2,16,17,[20][21][22]. Although the optical properties of the monolayer PdS2, electron transport properties and stability of the bilayer and bulk PdS2 have been studied in references [2,23,24], there are very few studies on the first principles analysis of the orthorhombic PdS2. It is a need of analysis for the optical and piezoelectric properties of the orthorhombic PdS2 under strains with different magnitudes.…”

Section: Hementioning

confidence: 99%

Optical and Piezoelectric Properties of Strained Orthorhombic PdS₂

Deng

Tao

Mei

et al. 2019

IEEE Trans. Nanotechnology

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We investigate optical and piezoelectric properties of the orthorhombic PdS2 under symmetrical biaxial tensile strains with various magnitudes. The ab initio simulation results found that the peaks of the refractive index, extinction coefficient, absorption coefficient and reflectivity of the orthorhombic PdS2 red-shift with the tensile strains. Specifically, we discover that the absorption coefficient of the strained orthorhombic PdS2 (4.01×10 5 /cm-5.52×10 5 /cm) is much higher than traditional optoelectronics, piezoelectric and piezophototronic materials such as Si, Ge, GaInAs, ZnO and monolayer MoS2 demonstrating much wider absorption spectrum (670 nm-1033 nm). Moreover, the piezoelectric constant of the orthorhombic PdS2 is calculated from 0 to 8% tensile strains. Simulation results show the orthorhombic PdS2 with 4% tensile strain has a strong piezoelectric effect (1.33 C/m 2), which is 100-5000 times higher than other deformation magnitudes. The results indicate that the orthorhombic PdS2 will have potential application in piezophotonic and piezoelectric devices.

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Experimental and Theoretical Investigation on the Relative Stability of the PdS₂‐ and Pyrite‐Type Structures of PdSe₂.

Cited by 7 publications

References 1 publication

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

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

Quasiparticle band structures of bulk and few-layer PdSe2 from first-principles GW calculations

Optical and Piezoelectric Properties of Strained Orthorhombic PdS₂

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Experimental and Theoretical Investigation on the Relative Stability of the PdS2‐ and Pyrite‐Type Structures of PdSe2.

Cited by 7 publications

References 1 publication

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

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

Quasiparticle band structures of bulk and few-layer PdSe2 from first-principles GW calculations

Optical and Piezoelectric Properties of Strained Orthorhombic PdS2

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Product

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Experimental and Theoretical Investigation on the Relative Stability of the PdS₂‐ and Pyrite‐Type Structures of PdSe₂.

Optical and Piezoelectric Properties of Strained Orthorhombic PdS₂