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

Abstract

Dimensionality can strongly influence the magnetic structure of solid systems. Here, we predict theoretically and confirm experimentally that the antiferromagnetic (AFM) ground state of bulk gadolinium germanide metalloxene, which has...

Unveiling the stacking-dependent electronic properties of the 2D ultrathin rare-earth metalloxenes family LnX2 (Ln = Eu, Gd, Dy; X = Ge, Si)

“…The overlap with the calculated states demonstrates that the data are in very good agreement with the DFT predictions for pristine films (see also ref. 10), confirming that the in situ grown films have a different atomic structure as compared to the SiO x -capped ones.…”

“…Next, the geometry of the topmost buckled honeycomb Ge atomic sheet is also different: the upper Ge atom is located at the T 1 site (which is the same as in the EuGe 2 case), but the lower Ge atom is now located at the H 3 site (instead of the T 4 site in the EuGe 2 case). 10 However, the Gd atoms are positioned at the centers of the honeycomb buckled germanene lattice, like in the case of Eu, which is seen in the top-view atomic model (Fig. 1(c)).…”

“…22 In particular, surface doping of the films can significantly alter the electronic and structural properties of thin films, changing their electronic and magnetic properties. 23 Recently, a pure antiferromagnetic (AFM) order was found for in situ grown LnX 2 10 films, as compared to FM order fingerprints observed in SiO x capped ones. 24–26…”

“…Rare earth metalloxenes (LnX 2 ) is a class of layered materials where honeycomb-like layers of semiconductor (Ge or Si) are separated by layers of rare-earth atoms of lanthanide series (Ln). 4–10 The layered character, availability of epitaxial growth on semiconducting substrates and a variety of lanthanide elements make LnX 2 a playground for studying the magnetism and transport in ultrathin film limit. Indeed, these systems demonstrated fingerprints of strong 2D ferromagnetic (FM) ordering in the monolayer (ML) limit, 11 together with high carrier mobility, 12 non-trivial topology 13 and remarkable transport phenomena.…”

“…14 The electronic band structures of some LnX 2 films were investigated through angle resolved photoemission spectroscopy (ARPES) 15–20 and density functional theory (DFT) studies. 10,20,21 However, a systematic study treating the electronic properties of these films as a function of thickness, Ln and host X element is still missing. The electronic and magnetic properties of LnX 2 films are furthermore expected to be sensitive to external perturbations, such as strain, charge doping and electric field.…”