Assessing the sensitivity of electron momentum densities and Fermi surfaces to different exchange-correlation approximations.

Density-functional theory has been remarkably successful at predicting the Fermi surfaces of a wide variety of metallic systems, these being tested by a range of experimental techniques. Yet, in some cases these predictions can be more successful than in others. For example, whereas the experimentally measured Fermi surface of Mo is accurately predicted by LDA calculations, notable differences have been observed for Cr [1]. By performing various calculations (including SCAN [2] and QSGW [3]) we have investigated the extent to which this discrepancy, as well as those in other materials, can be attributed to the exchange-correlation approximation. Observed improvements to Fermi surface predictions will be discussed.

[1] S. B. Dugdale et al., A high-resolution Compton scattering study of the Fermi surface of Cr, J. Phys. Chem. Solids 61, 361 (2000).
[2] J. Sun, A. Ruzsinszky, and J. P. Perdew, Strongly Constrained and Appropriately Normed Semi-local Density Functional, Phys. Rev. Lett. 115, 036402 (2015).
[3] M. van Schilfegaarde, T. Kotani, and S. Faleev, Quasiparticle Self-Consistent GW Theory, Phys. Rev. Lett. 96, 226402 (2006).