All-electron GW quasiparticle band structures of group 14 nitride compounds

Abstract

We have investigated the group 14 nitrides (M3N4) in the spinel phase (γ-M3N4 with M = C, Si, Ge, and Sn) and β phase (β-M3N4 with M = Si, Ge, and Sn) using density functional theory with the local density approximation and the GW approximation. The Kohn-Sham energies of these systems have been first calculated within the framework of full-potential linearized augmented plane waves (LAPW) and then corrected using single-shot G0W0 calculations, which we have implemented in the modified version of the Elk full-potential LAPW code. Direct band gaps at the Γ point have been found for spinel-type nitrides γ-M3N4 with M = Si, Ge, and Sn. The corresponding GW-corrected band gaps agree with experiment. We have also found that the GW calculations with and without the plasmon-pole approximation give very similar results, even when the system contains semi-core d electrons. These spinel-type nitrides are novel materials for potential optoelectronic applications because of their direct and tunable band gaps.

Pressure‐Tuneable Visible‐Range Band Gap in the Ionic Spinel Tin Nitride

“…Highly stable materials are usually wide-gap insulators, where covalencyd ominates the ionic exchange,s uch as diamond, [45] MgO, [46] and LiH, [47] whereas the enhanced stability of Sn 3 N 4 to applied pressure and temperature can be attributed to its dominant ionic character.Wedemonstrate control of structure via selective thermodynamic conditions and the tunability of the band gap across the entire visible range,a ni nsight into future chemical doping. Thed ependencyo fr ecovered states on decompression pathways and rates suggests tunability to desired electronic gaps.L argescale samples may be accessed via large-volume static or shock-recovered dynamic techniques.S n 3 N 4 is the first ionic semiconductor demonstrated to have such stability and technologically-useful electronic response.T he mechanism governing pressure-mediated band gap opening is solely due to the nature of the bonding,and our preliminary calculations on spinel Ge 3 N 4 and Si 3 N 4 as well as previous data [29] suggest asimilar pressure-mediated band gap opening. Such chemistry can be sought in similar systems,potentially defining anew class of simple ionic semiconductor materials.…”

“…Meanwhile,o ur value lies close to our band gap calculated with as ingle-shot Greensf unction (G 0 W 0 ) approach À1.4 eV and is within the range of prior values reported from computational methods:1 .1-1.55 eV from density functional theory (DFT), modified Becke-Johnson, and single-shot Greensf unction (G 0 W 0 )a pproaches. [16,[28][29][30] On compression in ad iamond anvil cell at room temperature,S n 3 N 4 first becomes red and ultimately transparent to visible light ( Figure 1a). Measurements of the optical absorption ( Figure 1b)r eveal that the increase in transparency corresponds to ac ontinuous blue-shift of the optical gap as af unction of pressure at ar ate of about 17 meVGPa À1 , reaching av alue of 3.0 eV at pressures of about 100 GPa (Figure 1c).…”

All-electron self-consistentGWin the Matsubara-time domain: Implementation and benchmarks of semiconductors and insulators

“…In this paper, we build upon an all-electron GW code we have already developed 11,41 by calculating Σ within the Matsubara-time domain, which improves the code's computational efficiency and provides scGW calculations. We implement this method in conjunction with the CPE to solve for the quasiparticle energies in the real-frequency domain.…”

Metallization and positive pressure dependency of bandgap in solid neon

“…The GW calculations were performed with the self-consistent GW approach in the Matsubara implementation with the diagonal approximation. 39,40 The GW bandgap corrections were determined within an accuracy of 0.1 eV after converging the number of bands (40).…”