Electronic signatures of successive itinerant, antiferromagnetic transitions in hexagonal La₂Ni₇

Abstract

We use high-resolution angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations to study the electronic and magnetic properties of La2Ni7, an itinerant magnetic system with a series of three magnetic transition temperatures upon cooling, which end in a small moment antiferromagnetic (smAFM) ground state. Our APRES data reveal several electron and hole pockets that have hexagonal symmetry near the $\Gamma$ point. We observe significant reconstruction of the band structure upon successive magnetic transitions at T1=61 K, T2= 57 K and T3=42 K. Several features observed in ARPES data were reasonably well reproduced by DFT calculations, while others were not. In particular, the flat band near $Ef predicted by DFT in AFM state, was seemingly absent in ARPES data. Our results detail the effects of magnetic ordering on the electronic structure in a Ni-based small moment antiferromagnet and highlight challenges of current computational methods.

Interplay between magnetic order and electronic band structure in ultrathin GdGe2 metalloxene films

“…29–33 In particular, ARPES, in combination with ab initio density-functional calculations (DFT), can give a clue on the exact magnetic structure. 34–36 In the present study we investigate by ARPES and DFT the electronic and magnetic structure of Gd germanide metalloxene films grown on Ge(111). Our results show that the AFM order remains the ground state of the films down to the ultrathin limit of 2 and 3 TL.…”