Tuning the electronic structures and transport coefficients of Janus PtSSe monolayer with biaxial strain

Abstract

Due to their great potential in electronics, optoelectronics and piezoelectronics, Janus transition metal dichalcogenide (TMD) monolayers have attracted increasing research interest, the MoSSe of which with sandwiched S-Mo-Se structure has been synthesized experimentally. In this work, the biaxial strain dependence of electronic structures and transport properties of Janus PtSSe monolayer is systematically investigated by using generalized gradient approximation (GGA) plus spin-orbit coupling (SOC). Calculated results show that SOC has a detrimental effect on power factor of PtSSe monolayer, which can be understood by considering SOC effects on energy bands near the Fermi level. With a/a0 from 0.94 to 1.06, the energy band gap firstly increases, and then decreases, which is due to the position change of conduction band minimum (CBM). It is found that compressive strain can increase the strength of conduction bands convergence by changing relative position of conduction band extrema (CBE), which can enhance n-type ZTe values. Calculated results show that compressive strain can also induce the flat valence bands around the Γ point near the Fermi level, which can lead to high Seebeck coefficient due to large effective masses, giving rise to better p-type ZTe values. The calculated elastic constants with a/a0 from 0.94 to 1.06 all satisfy the mechanical stability criteria, which proves that the PtSSe monolayer is mechanically stable in the considered strain range. Our works further enrich studies of Janus TMD monolayers, and can motivate farther experimental works.

Electronic, optical, and thermoelectric properties of Janus In-based monochalcogenides

“…The spin-orbit splitting values in In 2 SSe and In 2 SeTe monolayer are respectively 0.203 eV and 0.304 eV. Previously, the high spin-orbit splitting values have been also found for Janus monolayers PtSSe (0.280 eV) [45] and SnSSe (0.266 eV) [44]. Also, spin splitting of the uppermost valence band in Janus dichalcogenide WSeTe monolayer up to 0.46 eV [46] and high valley spin splitting (0.449 eV) around the K point has been found in WSSe monolayer due to the SOC effect [47].…”

Two-Dimensional Platinum Diselenide: Synthesis, Emerging Applications, and Future Challenges

“…4. 2D Janus materials have attracted extensive attentions due to their unique structure, electronic, and optoelectronic properties [227][228][229]. The formation of Janus crystal structure broke the inversion and mirror symmetry, leading to an intrinsic built-in electric field.…”

Effects of electric field and strain engineering on the electronic properties, band alignment and enhanced optical properties of ZnO/Janus ZrSSe heterostructures

“…To date, several Janus materials have been developed, such as Janus PtSSe, 34,35 SnSSe 36 and ZrSSe 37,38 monolayers. Guo et al, 37 via rst-principle calculations demonstrated that the Janus ZrSSe monolayer is dynamically and mechanically stable.…”