2019/10/03 by Xiangzhou Zhu, Alexander Edström, Å. Edström +1 · 27 citations
Chemistry · Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Chemistry #Computational chemistry #Condensed matter physics #Density functional theory #Heisenberg model #Magnetic and transport properties of perovskites and related materials #Physics #Physics of Superconductivity and Magnetism #Superexchange #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.101.064401
published in Physical review. B./Physical review. B 101(6) (American Physical Society) · 10 pages, 9 figures
arxiv created 2019/10/03 · openalex created_date 2019/10/10 · openalex publication_date 2020/02/03 · arxiv updated 2020/02/12 · openalex updated_date 2026/08/06
We calculate Heisenberg-type magnetic exchange interactions for SrMnO3 under isotropic volume expansion by using an approach that is based on total-energy variations due to infinitesimal spin rotations around a given reference state. Our total-energy calculations using density-functional theory (DFT) indicate a transition from antiferromagnetic to ferromagnetic coupling for increasing interatomic distances, corresponding to a sign change of the nearest-neighbor exchange interaction. This sign change cannot easily be understood from a standard superexchange mechanism. Furthermore, the exchange interaction strongly depends on the corresponding reference state. This ``non-Heisenberg'' behavior increases with increasing volume and is also confirmed through noncollinear DFT calculations. An orbital- and energy-resolved decomposition of the exchange coupling suggests that an increased partial occupancy of eg orbitals near the Fermi level is crucial both for the sign change and the non-Heisenberg behavior of the nearest-neighbor interaction. Furthermore, even though both eg and t2g contributions to the exchange interactions decay exponentially for large interatomic distances, the eg contribution remains surprisingly strong over relatively large distances along the crystal axes.