Computational study of the thermoelectric properties and lattice dynamics of Li2MN2 (M = Zr or Hf)

Abstract

This study systematically examines the lattice dynamics of Li2MN2 (M = Zr or Hf), with the aim of unraveling the factors contributing to its unique thermal transport properties using first-principles calculations. Both compounds are found to be energetically and dynamically stable, and our results for their lattice parameters and bond lengths are in good agreement with the available experimental data. The transport properties exhibit strong anisotropic behavior due to the layered structure. Li2ZrN2 possesses a low lattice thermal conductivity (1.52 Wm−1K−1) along the a-axis at 1000 K, owing to the significant reduction in phonon lifetime caused by the rattling behavior of Zr. The present study may provide valuable insights when exploring the role of lattice dynamics in minimizing the lattice thermal conductivity of transition metal nitrides and their prospective energy harvesting applications.