Mechanical properties of monolayer GaS and GaSe crystals

Abstract

The mechanical properties of monolayer GaS and GaSe crystals are investigated in terms of their elastic constants: in-plane stiffness (C), Poisson ratio (ν), and ultimate strength (σ U ) by means of first-principles calculations. The calculated elastic constants are compared with those of graphene and monolayer MoS 2 . Our results indicate that monolayer GaS is a stiffer material than monolayer GaSe crystals due to the more ionic character of the Ga-S bonds than the Ga-Se bonds. Although their Poisson ratio values are very close to each other, 0.26 and 0.25 for GaS and GaSe, respectively, monolayer GaS is a stronger material than monolayer GaSe due to its slightly higher σ U value. However, GaS and GaSe crystals are found to be more ductile and flexible materials than graphene and MoS 2 . We have also analyzed the band-gap response of GaS and GaSe monolayers to biaxial tensile strain and predicted a semiconductor-metal crossover after 17% and 14% applied strain, respectively, for monolayer GaS and GaSe. In addition, we investigated how the mechanical properties are affected by charging. We found that the flexibility of single layer GaS and GaSe displays a sharp increase under 0.1e/cell charging due to the repulsive interactions between extra charges located on chalcogen atoms. These charging-controllable mechanical properties of single layers of GaS and GaSe can be of potential use for electromechanical applications.

Two‐Dimensional GaX/SnS2 (X = S, Se) van der Waals Heterostructures for Photovoltaic Application: Heteroatom Doping Strategy to Boost Power Conversion Efficiency

“…The band structure of SnS 2 is displayed by the blue line and SnS 2 has an indirect band gap of 1.57 eV (blue arrow). All results for the band structure of monolayers are well consistent with other simulation results . Figure c,d show the projected band structures of the GaS/SnS 2 and GaSe/SnS 2 heterostructures, respectively.…”

“…All results for the band structure of monolayers are well consistent with other simulation results. [19,40] Figure 2c www.advancedsciencenews.com www.pss-rapid.com blue dots represent occupancy of SnS 2 . The different sizes of dots indicate different occupancy: the bigger size indicates a larger occupancy.…”

Engineering of electronic and optical properties of monolayer gallium sulfide/selenide in presence of intrinsic atomic defects

“…The lattice constants (a 0 ) of GaS and GaSe monolayers are 3.584 Å and 3.742 Å, respectively. These results are consistent with those of other studies [12,17,18]. Next, we compute the spin-polarized band structure, zero-bias transmission spectrum, and dielectric function of the pristine GaX monolayer as shown in figure 2.…”

“…Moreover, they found the band gap of these materials can be set by employing mechanical deformation. The mechanical properties of GaX monolayer were reported by Yagmurcukardes et al [18]. They indicated that the GaS monolayer is more rigid than the GaSe monolayer.…”

Stable ultra-thin CdTe crystal: a robust direct gap semiconductor

“…In addition to graphene, other 2D crystals such as germanene, 2,3 silicene, 4,5 stanene, 6,7 transition-metal dichalcogenides (TMDs), [8][9][10][11][12] and post-transitionmetal chalcogenides (TMCs) [13][14][15] have been predicted and successfully synthesized. One of the most prominent members of 2D crystals is MoS 2 .…”