Comparatively study of the electronic structure, thermal expansivity and lattice thermal conductivity of CaOn (n = 1, 2, 3)

• Published in: Physica. B, Condensed matter Vol. 644; p. 414216
• Main Authors: Ma, Yangyang, Yang, Shu, Dong, Wenxin, He, Kaihua
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2022
• Subjects: Electronic structure; First principles; Lattice thermal conductivity; Thermal expansivity; First principles; Electronic structure; Thermal expansivity; Lattice thermal conductivity
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2022.414216

Recent studies reported that Ca and O can form calcium peroxide (CaO2) and calcium ozonide (CaO3) at high pressure, while the knowledge of their physical properties is limited. In this study, the first principles were adopted to investigate the electronic structure, thermal expansivity (α) and lattice thermal conductivity (κlatt) of CaOn. The density of states (DOS) show that three compounds are semiconductors, and the split of O 2s orbitals are taken place owing to the O–O bonds in CaO2 and CaO3. Meanwhile, the contribution of the lowest conduction band varies significantly with the change of the number of O atom. The calculations indicate that α is in the order of αCaO3>αCaO2>αCaO, which is majorly determined by the Grüneisen constant (γ). The calculated κlatt shows an opposite order to α. The further discussion unveils that the anharmonic scattering rates of three compounds account for the magnitude of κlatt.