Theoretical study of the band gap of SrS in GW approximation

Abstract

Using the first-principles pseudopotential method within a local density approximation of the density functional theory (DFT), the structural, electronic properties of SrS in the NaCl(B1) and CsCl(B2) structures have been studied. The calculated lattice parameters, bulk modulus and elastic constants are in excellent agreement with the experiment value and other theoretical value, whereas the minimum gap error is as high as 50.46% in the B1 structure. To get the reliable band gap values of the B1 structure, we employ the GW (G is Green's function and W is the screened Coulomb interaction) approximation method. The result in GW approximation improves the band gap value of the B1 structure greatly and agrees with the value of experimental measurement. And we also predict the band gap value of the B2 structure reliably by GW approximation.

Spectroscopic properties of high-temperature sintered SrS:0.05%Ce3+ under high hydrostatic pressure

“…Such behavior of the PL of SrS:Ce 3+ can be attributed to the pressure induced phase transition at 180 kbar. 1,2 The luminescence was too weak to measure the PLE spectra under high pressure. However, due to the pressure shift of PLE bands we had to change the excitation to longer wavelengths for higher pressures.…”

“…1 Calculations performed using the first principles pseudopotential method within a local density approximation of density functional theory (DFT) shows that for both B1 and B2 structures SrS is an indirect band gap semiconductor with the maximum of the valence band in the G point and the minimum of the conduction band in the X point and M point of the Brillouin zone, for B1 and B2 structures, respectively. 2 In SrS the Ce 3+ ion replaces Sr 2+ in octahedral coordination of the S 2À ions. In such a case the excited 5d electronic manifold splits into two levels -the lower six-fold degenerate (including spin) t 2g and the higher four-fold degenerate e g .…”

A novel theoretical design of electronic structure and half-metallic ferromagnetism in the 3d (V)-doped rock-salts SrS, SrSe, and SrTe for spintronics

“…À1 , where G max is the largest vector in the Fourier expansion. For the sampling of the Brillouin zone, we utilized the Monkhorst-Pack mesh 39,40 of (4 Â 4 Â 4) k-points for SrZ 34,41 and (4 Â 4 Â 2) for Sr 0.875 V 0.125 Z (Z ¼ S, Se and Te), 34 where the self-consistent convergence of the total energy was at 0.1 mRy.…”