Unveiling electron correlation in semiconducting Heusler FeVSb by angle-resolved photoemission and dynamical mean field theory

Electron-electron correlations are responsible for many of the exotic properties of transition metal oxides and chalcogenides; however, the role of correlations in transition metal Heusler compounds is often overlooked. Here, combining angle-resolved photoemission spectroscopy (ARPES) and dynamical mean field theory (DMFT), we directly probe the single particle spectral function of the Heusler FeVSb. ARPES measurements on epitaxial FeVSb films reveal a mass renormalization of m^* / m_bare = 1.4, where m_bare is the mass from DFT-LDA calculations that do not include a Hubbard U. This mass renormalization lies in dramatic contrast to other Heuslers LnPt(Sb,Bi) (Ln = lanthanide) [1-3] and CoTiSb [4], for which bare DFT calculations are in quantitative agreement with ARPES. By treating the many-body interactions more accurately at the level of DMFT, we quantitatively reproduce the measured electronic structure and comment on the differences between FeVSb and other Heuslers. Our work calls for a re-thinking of the role of correlations in FeVSb and in Heuslers more generally.

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