Thermoelectric Properties of 2D‐Janus Monochalcogenides: Anisotropic Electronic and Phonon Transport

Abstract Reduction in symmetry has emerged as an effective approach to better the transport parameters in 2D materials. Motivated by this, using Density Functional Theory and Boltzmann transport theory, the thermoelectric properties of the Janus monochalcogenides , , and (X, Y = S, Se, Te) derived from parent group IV‐VI chalcogenides MX (M = Ge, Sn; X = S, Se, Te) that have turned out to be promising thermoelectric materials, are investigated. It is found that while the unconventional band structures of these Janus compounds lead to highly anisotropic, increased anharmonicity and reduced phonon group velocity contribute to the low lattice thermal conductivity of these compounds. The combination of multivalley and pudding mold features in electronic band structures enhances the power factor (PF), resulting in optimal thermoelectric figure of merit of 1.61 (1.62), 1.70 (1.61), and 1.56 (0.84) for n‐type (p‐type) , , and , respectively, at 800 K. The results suggest that these Janus compounds are promising materials for thermoelectric applications.