Efficient workflow for treating thermal and zero-point contributions to formation enthalpies

The formation enthalpy, quantifying the enthalpy of a compound with
respect to its elemental references, is a key parameter for predicting the
thermodynamic stability of materials thus enabling data-driven materials
design. Although for instance zero-point vibrational and thermal
contributions to the formation enthalpy can be quite substantial reaching
absolute values of up to ∼ 50 meV/atom for ionic systems such as
oxides, they are often neglected in ab initio workflows.
Here, we first calculate the thermal and zero-point contributions accurately
from a quasi-harmonic Debye model. At room temperature,
they largely cancel each other due to the different bond stiffness of
compound and references reducing the total vibrational contribution
to maximally ∼ 20 meV/atom [1]. Moreover, the vibrational contributions
can be parametrized within the coordination corrected enthalpies
(CCE) method completely eliminating the need to compute
these terms explicitly. On this basis, using only 0 K ab initio data
as input, a workflow can be designed providing access to formation
enthalpies at different temperatures from the AFLOW-CCE tool [2].
[1] R. Friedrich et al., npj Comput. Mater. 5, 59 (2019).
[2] R. Friedrich et al., Phys. Rev. Mater. 5, 043803 (2021).