Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for studying the structural and electronic properties of paramagnetic solids. However, the interpretation of paramagnetic NMR spectra is often challenging as a result of the interactions of unpaired electrons with the nuclear spins of interest. In this work, we extend the formalism of the paramagnetic NMR shielding in the presence of spin-orbit coupling towards solid systems with multiple paramagnetic centers. We demonstrate how the single-ion electron paramagnetic resonance g tensor is defined and calculated in periodic paramagnetic solids. We then calculate the hyperfine tensor and the g tensor with density functional theory to show the validity of the presented model and we further demonstrate how these interactions can be combined to give the overall paramagnetic shielding tensor, σs. The method is applied to a series of olivine-type LiTMPO4 materials (with TM=Mn, Fe, Co, and Ni) and the corresponding Li7 and P31 NMR spectra are simulated. We analyze the effects of spin-orbit coupling and of the electron-nuclear magnetic interactions on the calculated NMR parameters. A detailed comparison is presented between contact and dipolar interactions across the LiTMPO4 series, in which the magnitudes and signs of the nonrelativistic and relativistic components of the overall isotropic shift and shift anisotropy are computed and rationalized.
| Original language | English |
|---|---|
| Article number | 054412 |
| Number of pages | 11 |
| Journal | Physical Review B |
| Volume | 95 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 8 Feb 2017 |
Bibliographical note
Funding Information:R.P. acknowledges financial support from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme (FP7/2007-2013) under REA Grant Agreement No. 317127. Via our membership of the UK's HPC Materials Chemistry Consortium, which is funded by EPSRC (Grant No. EP/L000202), this work made use of the facilities of ARCHER, the UK's national high-performance computing service, which is funded by the Office of Science and Technology through EPSRC's High End Computing Programme. Research was also carried out at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10886.
Publisher Copyright:
© 2017 American Physical Society.