Effects of iron spin transition on the electronic structure, thermal expansivity and lattice thermal conductivity of ferropericlase: a first principles study

• Published in: Scientific reports Vol. 9; no. 1; p. 4172
• Main Authors: Song, Yalan, He, Kaihua, Sun, Jian, Ma, Chaojie, Wan, Miao, Wang, Qingbo, Chen, Qili
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 12.03.2019; Nature Publishing Group
• Subjects: 119/118; 639/33/445/330; 704/2151/2809; Heat conductivity; Humanities and Social Sciences; Iron; multidisciplinary; Pressure; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-40454-4

The effects of the spin transition on the electronic structure, thermal expansivity and lattice thermal conductivity of ferropericlase are studied by first principles calculations at high pressures. The electronic structures indicate that ferropericlase is an insulator for high-spin and low-spin states. Combined with the quasiharmonic approximation, our calculations show that the thermal expansivity is larger in the high-spin state than in the low-spin state at ambient pressure, while the magnitude exhibits a crossover between high-spin and low-spin with increasing pressure. The calculated lattice thermal conductivity exhibits a drastic reduction upon the inclusion of ferrous iron, which is consistent with previous experimental studies. However, a subsequent enhancement in the thermal conductivity is obtained, which is associated with the spin transition. Mechanisms are discussed for the variation in thermal conductivity by the inclusion of ferrous iron and the spin transition.