Multipolar exchange interaction: Difference between revisions

Revision as of 07:28, 24 August 2015

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== Compute Coupling Constants ==

Calculation of multipolar exchange interactions remains a challenging issue in many aspects. Although there were many works based on fitting the model Hamiltonians with experiments, proposals based on first-principle schemes remain lacking. Currently there are two studies implemented first-principles approach to explore multipolar exchange interactions. An early study was developed in 80's. It is based on a mean field approach that can greatly reduce the complexity of coupling constants induced by RKKY mechanism, so the multipolar exchange Hamiltonian can be described by just a few unknown parameters and can be obtained by fitting with experiment data <ref> R. Siemann and B. R. Cooper, Phys. Rev. Lett. 44, 1015 (1980) </ref>. Later on, a first-principles approach to estimate the unknown parameters was further developed and got good agreements with a few selected compounds, e.g. cerium momnpnictides <ref> J. M. Wills and B. R. Cooper, Phys. Rev. B 42, 4682 (1990) </ref>. Another first-principle approach was also proposed recently<ref name="multipolar exchange"/>. It maps all the coupling constants induced by all static mechanisms to a series of LDA+U total energy calculations and got qualitative agreement with uranium dioxide.

== Reference ==