Fermi surface of LaFe2P2 - a detailed density functional study

T Förster (1) , I Kraft (2) , Ilya Sheikin (3) , A Bianchi (4) , J. Wosnitza (1) , H Rosner (2)

1 Dresden High Magnetic Field Laboratory
2 CPfS - Max Planck Institute for Chemical Physics of Solids
3 LNCMI-G - Laboratoire national des champs magnétiques intenses - Grenoble
4 UdeM - Université de Montréal

Angular-dependent de Haas-van Alphen measurements allow to map Fermi surfaces in great detail with high accuracy. Density functional electronic-structure calculations can be carried out with high precision, but depend crucially on the used structural information and the applied calculational approximations. We report in a detailed study about the sensitivity of the calculated electronic band structure of the 122 compound LaFe 2 P 2 on (i) the exact P position in the unit cell, parametrized by a so-called z parameter, and on (ii) the treatment of the La 4f states. Depending on the chosen exchange and correlation-potential approximation, the calculated z parameter varies slightly and corresponding small but distinctive differences in the calculated band structure and Fermi-surface topology appear. Similarly, topology changes appear when the energy of the mostly unoccupied La 4f states is corrected regarding their experimentally observed position. The calculated results are compared to experimental de Haas-van Alphen data. Our findings show a high sensitivity of the calculated band structure on the pnictide z position and the need for an accurate experimental determination of this parameter at low temperatures, and in particular the need of a sophisticated treatment of the La 4f states. Thus, this is not only crucial for the special case of LaFe 2 P 2 studied here, but of importance for the precise determination of the band structure of related 122 materials and La containing compounds in general.

Domaines: Electrons fortement corrélés [cond-mat.str-el]

T Förster, I Kraft, Ilya Sheikin, A Bianchi, J. Wosnitza, et al.. Fermi surface of LaFe2P2 - a detailed density functional study. Journal of Physics: Condensed Matter, 2019, 32 (2), pp.025503. ⟨10.1088/1361-648X/ab45fa⟩. ⟨hal-02345544⟩