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In this paper, we replace the sulfur atom with other atoms based on rhenium disulfide. The monolayer is combined and adjusted on the original basis. Based on the first principle, we studied the structural, electronic and optical properties of the transition metal monolayers of ReX 2 and ReXS (X=S, Se, Te). The structure resembles a 'sandwich'. It is worth noting that ReSeS and ReSe 2 not only retain the direct band gap properties, but also have a large band gap, when the strain changes, not only the band gap changes, but also the nature of the band gap changes with each other. so they show good optical properties, and ReSe 2 and ReSeS have stronger absorption in the ultraviolet band. The band gap opened in ReSeS can be effectively adjusted by biaxial strain, and the band gap varies between direct and indirect.

Monolayers of transition metal ReX2 and ReSX (X=S, Se) have been proposed as new electronic materials for nanoscale devices. In this paper, there are three structures: ReS2, Janus ReSSe, and ReSe2. Based on the first-principles theory, we analyzed the structures, electronic properties, and Fermi speed. Remarkably, we studied the stability of structures of ReS2, Janus ReSSe, and ReSe2 monolayers under biaxial tensile and compressive strain by density functional approach. It is worth noting that when the strain changes, not only the band gap changes but also the band gap properties (direct and indirect) also change. The bond gaps decrease with the increase of tensile strain and compressive strain; Moreover, when the strain is greater than 0, the bond angle decreases as the strain increases, and when the strain is less than 0, the bond angle increases as the strain increases.

The nodal ring material has recently attracted wide attention due to its singular properties and potential applications in spintronics. Here, two-dimensional Zn3C6S6 is calculated and discussed by using first-principle calculations. We found that two-dimensional Zn3C6S6 can generate a nodal ring at 10% compressive strain, and the existence of the ring is proved by a partial charge density map. And as the compressive strain increases, the nodal ring does not disappear. At the same time, the stability of the electron-orbit coupling to the nodal ring is applied. Our findings indicate that the two-dimensional Zn3C6S6 is promising in new electronic and spintronic applications.