Electronic and structural properties of strontium chalcogenides SrS, SrSe and SrTe

Abstract

We present the results of a first-principles study of the electronic and structural properties of strontium chalcogenides, SrS, SrSe and SrTe. The computational method is based on the full-potential linear muffintin orbitals method (FP-LMTO) augmented by a plane-wave basis (PLW). The exchange and correlation energy is described in the local density approximation (LDA) using the Perdew-Wang parameterization including a generalized gradient approximation (GGA). The calculated results of the structural properties are given for the NaCl (B1) and CsCl (B2) structures. We have also carried out band-structure calculations for the three considered compound, but only for the NaCl (B1) structure. A reasonable agreement is found from the comparison of our results with other theoretical calculations and experimental data.

Tuning bands of PbSe for better thermoelectric efficiency

“…The slightly larger k L reduction comes from larger mass contrast between Sr and Pb (compared with that between Se and Te). The much larger alloy scattering potential U (U around 1 eV for n-type PbSe 1Àx Te x ) is probably linked to the larger mismatch of valence band energy: the electron affinity of SrSe is 57 1.8 eV and its band gap (G-X) is 58,59 3.8 eV, the top of its valence band at G point is thus 5.6 eV below the vacuum level. On the other hand the work function of PbSe is 60 4.6 eV and the band gap 0.3 eV, which means the top of its L valence band is 4.8 eV below the vacuum level: a 0.8 eV difference in band energy between PbSe and SrSe.…”

Theoretical study of the phonon properties of SrS

“…SrS has been found to undergo a first-order phase transition from the B1 structure to the B2 structure at 18 GPa, as shown by X-ray diffraction experiments [4]. In addition, considerable progress has been made in the theoretical description of its structural phase transformation under pressure, its electronic, optical, and elastic properties, and the volume dependence of energy gap of SrS [5][6][7][8][9][10][11][12][13][14][15][16]. Phonon properties of solids are important because they are closely associated with various fundamental solid-state properties, such as thermal expansion, specific heat, electron-phonon interaction, heat conduction, and thermal conduction of the lattice.…”

Theoretical investigation of phase transition properties in strontium chalcogenides using potential model

“…The high-pressure X-ray diffraction study show that all the strontium chalcogenides transform to the 8-fold-coordinated cesium chloride (B2) structure from their initial 6-foldcoordinated rocksalt (B1) structure, at 36 GPa in SrO [3,4], 18 GPa in SrS [5], 14.2 GPa in SrSe [6], and 12 GPa in SrTe [7]. There are a number of theoretical investigations on these compounds within the framework of ab inito calculations and different potential models concerning optical properties [8][9][10], electronic band structure, structure phase stability and elastic properties [11][12][13][14][15][16][17][18][19][20]. Although some of these calculations predict the phase-transition pressure quite close to the experimental values, but other properties like equation of state (compression), bulk modulus and the first-order pressure derivative of bulk modulus did not match with the experimental values.…”