High thermoelectric performance of a Sc₂Si₂Te₆ monolayer at medium temperatures: an ab initio study

Thermoelectric (TE) materials have attracted great attention in solving the problems in the waste heat field, while low figure of merit and poor material stability drastically limit their practical applications. In this work, a two-dimensional (2D) Sc₂Si₂Te₆ monolayer was systematically explored as a promising TE material via ab initio methods. The results reveal that the Sc₂Si₂Te₆ monolayer possesses an indirect band gap with a rhombohedral crystal phase and exhibits excellent dynamic stability. The lower electronic/lattice thermal conductivity and higher electron carrier mobility result in good n-type power factor parameters between 6.24 × 10¹⁰ and 1.5 × 10¹¹ W m^-1 s^-1 K^-2 from 300 to 700 K. Such combined merits of low thermal conductivity and high power factor parameters endow the Sc₂Si₂Te₆ monolayer with superior thermoelectric properties with figure of merit (ZT) values of 1.41 and 3.81 at 300 K and 700 K, respectively. This study presented here can shed light on the future design of various 2D materials for thermoelectric applications.