Hinge-like Co2S3and Co2Te3Nanosheets: Promising Two-Dimensional Optical, Thermoelectric, and Spintronic Materials

Abstract

In this study, the structural and physical properties of hinge-like Co2S3 and Co2Te3 nanosheets are predicted using spin-polarized density functional theory. Our calculations show that Co2S3 and Co2Te3 nanosheets are ferromagnetic semiconductors and antiferromagnetic metals in the ground state, respectively, and these nanosheets are dynamically and thermodynamically stable. According to the mean-field theory, Co2S3 and Co2Te3 nanosheets have the Néel temperature of 933 K and the Curie temperature of 285 K. Also, Co2Te3 nanosheets have unique properties such as significant total magnetic momentum (5.07 μB) and high magnetic anisotropy energy (2.62 meV). The examination of optical properties shows that Co2S3 and Co2Te3 nanosheets can be used in optoelectronic devices such as strong far- ultraviolet and ultraviolet absorbers, respectively. Calculating thermoelectric properties using Boltzmann’s theory shows that the Co2S3 nanosheet not only has ZT = 1 at 100 K but has significant thermoelectric efficiency at temperatures higher than room temperature (ZT = 0.97 at 700 K). Based on spin-dependent transport calculations, the current passing through Co2S3 (37.55 μA) and Co2Te3 (75 μA) nanosheets is higher than many 2D nanostructures, and the transport properties of these nanosheets are anisotropic. Therefore, Co2S3 and Co2Te3 nanosheets can be promising candidates for the development of nanoscale thermoelectric and spintronic devices.