First-principles calculations of lattice dynamics and thermal properties of polar solids

Abstract

Although the theory of lattice dynamics was established six decades ago, its accurate implementation for polar solids using the direct (or supercell, small displacement, frozen phonon) approach within the framework of density-function-theory-based first-principles calculations had been a challenge until recently. It arises from the fact that the vibration-induced polarization breaks the lattice periodicity, whereas periodic boundary conditions are required by typical first-principles calculations, leading to an artificial macroscopic electric field. The article reviews a mixed-space approach to treating the interactions between lattice vibration and polarization, its applications to accurately predicting the phonon and associated thermal properties, and its implementations in a number of existing phonon codes.

Phonon-assisted optical absorption in BaSnO3 from first principles

“…The LO-TO splitting is incorporated by calculating the dielectric constant and Born effective charges (shown in the Supplemental Material 57 ) and then using the scheme described in Ref. 58. The results are in good agreement with those obtained using elongated supercells along the (100) crystallographic direction to calculate the phonon frequencies at (q, 0, 0) for small q.…”

Atomistic and experimental study on thermal conductivity of bulk and porous cerium dioxide

“…The analytic contribution accounts for all the forces under the restricted periodic boundary conditions under which the averaged electric field is assumed to be zero. The nonanalytic contribution accounts the additional forces owing to non-zero averaged electric field 56 . The classical Newton’s second law of motion for describing the atomic vibrations for a polar solid is as shown in Eq.…”

First-principles study on structural, electronic, vibrational and thermodynamic properties of Sr10(PO4)6X2(X = F, Cl, Br)

“…It is generally known that LO-TO splitting can be considered into the dynamical matrix by a non-analytical contribution, which depends on the Born effective charge (BEC) tensor and the dielectric constant. [59][60][61] In the present work, BEC tensor (Z*) and macroscopic static dielectric constant tensor (3) of each apatite are calculated through the DFPT. The calculated diagonal elements Z* for 7 non-equivalent atoms are given in Table 4.…”