The lattice thermal conductivity of Cu2O was studied using ab initio density functional methods. The performance of generalized gradient approximation (GGA), GGA-PBE, and PBE0 exchange-correlation functionals was compared for various electronic and phonon-related properties. The 3d transition metal oxides such as Cu2O are known to be a challenging case for pure GGA functionals, and in comparison to the GGA-PBE the PBE0 hybrid functional clearly improves the description of both electronic and phonon-related properties. The most striking difference is found in the lattice thermal conductivity, where the GGA underestimates it as much as 40% in comparison to experiments, while the difference between the experiment and the PBE0 hybrid functional is only a few percent.
Calculations of lattice thermal conductivity of Cu2O using the generalized gradient approximation and hybrid density functional methods