High intrinsic $ZT$ in InP$_3$ monolayer at room temperature

TL;DR

This study predicts that InP₃ monolayer exhibits an exceptionally high thermoelectric figure of merit ($ZT$) of 2.2 at room temperature, making it a promising material for energy conversion applications.

Contribution

The paper introduces InP₃ monolayer as a new 2D thermoelectric material with record-high $ZT$ at room temperature based on quantum ballistic transport calculations.

Findings

$ZT$ of 2.2 at 300 K predicted for InP₃ monolayer

Remarkably low and isotropic phononic thermal conductivity due to flat lattice vibrations

High $ZT$ (>1.5) maintained under 1% mechanical strain

Abstract

Two-dimensional thermoelectric materials with a figure of merit $ZT$, which is greater than 2.0 at room temperature, would be highly desirable in energy conversion since the efficiency is competitive to conventional energy conversion techniques. Here, we propose that the indium triphosphide (InP$_3$) monolayer offers an extraordinary $ZT$ of 2.2 at 300 K by using quantum calculations within the ballistic thermal transport region. A remarkably low and isotropic phononic thermal conductivity is founded, which is due to flat lattice vibration modes. This low thermal conductivity takes a major responsibility to the impressively high $ZT$. Moreover, a large $ZT$ that is greater than 1.5 can be maintained, even if a 1% mechanic extension is applied on the lattice. These results suggest that the InP$_3$ monolayer is a promising candidate for low dimensional thermoelectric applications.