Electronic structure and exchange interactions of insulating double perovskite La2CuRuO6
2016 (English)In: PHYSICAL REVIEW B, ISSN 2469-9950, Vol. 94, no 6, 064427Article in journal (Refereed) Published
We have performed first-principles calculations of the electronic and magnetic properties of insulating double perovskite compound La2CuRuO6 (LCRO) which has recently been reported to exhibit intriguing magnetic properties. We derived a tight-binding Hamiltonian for LCRO based on the Nth-order muffin-tin orbital (NMTO) downfolding technique. The computed on-site energies and hopping integrals are used to estimate the dominant exchange interactions employing an extended Kugel-Khomskii model. This way the dominant exchange paths were identified and a low-energy spin model was proposed. The Green function method based on the magnetic force theorem has also been used to extract the exchange interactions to provide a more accurate estimation and to justify the model calculations. Our results show that the nearest neighbor (NN) Cu-Ru magnetic interactions are very much direction dependent and a strong antiferromagnetic next nearest neighbor Ru-Ru interaction along the crystallographic b axis is responsible for the magnetic frustration observed experimentally in this system. We argue that due to the broken symmetry, NN Cu-Ru interaction becomes stronger along one direction than the other, which essentially reduces the amount of frustration and helps the system to achieve an antiferromagnetic ground state at low temperature. A detailed microscopic explanation of the exchange mechanism is discussed. We also find that spin-orbit coupling effect is significant and causes a canting of the Ru spin with respect to the Cu moments.
Place, publisher, year, edition, pages
2016. Vol. 94, no 6, 064427
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:uu:diva-303267DOI: 10.1103/PhysRevB.94.064427ISI: 000381888500003OAI: oai:DiVA.org:uu-303267DiVA: diva2:971462
FunderSwedish Research CouncilKnut and Alice Wallenberg Foundation, 2013.0020 2012.0031eSSENCE - An eScience Collaboration