Structural, vibrational, elastic, electronic, and piezoelectric properties of binary γ−GeX and ternary γ−Ge2XX′

Two-dimensional Janus antimony chalcohalides for efficient energy conversion applications

“…In Bader charge analysis, Δ ρ Sb–Y (charge transfer from Sb to chalcogens) decreases as the atomic mass corresponding to the chalcogen increases but in the case of Δ ρ Sb–Y (charge transfer from Sb to halogens), an irregular trend is observed. A similar kind of irregular charge transfer behaviour for the case of halogens is observed in the case of MXY (M = Sb, As; X = Te, Se; Y = Br, I) 36 and γ-Ge 2 XX′ (X, X′ = S, Se and Te) 32 monolayers. The bond lengths d Sb–Y and d Sb–Z of SbYZ monolayers increase as the lattice constant “ a ” increases as we move down the chalcogen and halogen groups.…”

“…Accordingly, SbSCl and SbSeI are the most and least stable materials amidst the SbYZ Janus monolayers. The E C of SbYZ is comparable with the BiXY (X = S, Se and Te; Y = F, Cl, Br and I) (2.46–3.58 eV per atom) 30 and Ge 2 XX′ (X/X′ = S, Se and Te) (3.14–3.68 eV per atom) 32 monolayers.…”

“…, d 11 and d 31 . The piezoelectric properties of various Janus monolayers based on bismuth chalcogen halides, 30 bismuth oxyhalide, 31 group-IV monochalcogenides, 9 PtXO (X = S, Se), 27 γ-Ge 2 XX′ (X, X′ = S, Se, and Te), 32 SnSSe, 33 MoSTe, 34 WXO (X = S, Se, and Te), 20 X 2 PAs (X = Si, Ge, and Sn), 35 MXY (M = Sb and As; X = Te and Se; Y = Br and I) 36 and TiXY (X, Y = Cl, Br, and I) 37 have been reported.…”

Intrinsic Coupling between Piezoelectric and Electronic Transport Properties in Janus γ-GeSnXO (X = S, Se) Monolayers with Vertical Piezoelectricity

“…It is known that the band gap of HSE06 is more realistic than the band gap checked by the PBE function. These band gap values of γ-GeSnXO sheets are greater than those of γ-Ge 2 XY/γ-Sn 2 XY (X/Y = S, Se, and Te) sheets. , In Figure c,d, the black, purple, green, and red spheres represent Ge, Sn, S (or Se), and O atoms, respectively. The projected energy band can also analyze the position of band edges and the specific providers of energy bands near the Fermi surface.…”

“…Subsequently, nonzero out-of-plane piezoelectric characteristics are generated. In previous studies, scientists systematically studied the structure, vibration, electronic, mechanical, and piezoelectric properties of binary γ-GeX and ternary γ-Ge 2 XY (X/Y ≕ S, Se, and Te) monolayers. − In this work, we studied the ternary system, the physical mechanism, and the piezoelectric properties of the γ-GeSnXO (X = S, Se) Janus monolayer. Similar structures, γ-GeX and γ-SnX (X = S, Se, and Te) monolayers, are synthesized in the experiment. , Based on the γ-GeX structure, one layer of Ge atoms is replaced by Sn atoms and one layer of X atoms is replaced by O atoms.…”