Unexpectedly high thermoelectric performance of anisotropic ZrClmonolayer.

Recently, the HfCl-type materials as functional materials have attracted broad interest because of their enormous potential in thermoelectric (TE) applications. However, relevant investigations are still scarce up to now. To explore the HfCl-type materials with excellent TE properties, we focus on the TE properties of ZrClmonolayer and calculate the TE parameters based on first-principles calculations and Boltzmann transport equation. Although, as compared to some typical TE materials, it exhibits better heat transport and thus higher lattice thermal conductivity, the figure of merits () of both p-type and n-type ZrClreach an unexpectedly high value of 3.90 and 3.60, respectively, owing to the larger electrical conductivity and higher power factor. Additionally, owing to the prominent difference in electrical conductivity between the- and-direction, strong anisotropy invalues is observed. Our study reveals that both n-type and p-type ZrClmonolayers have the potential for future TE applications.