Self-texturizing electronic properties of a 2-dimensional GdAu₂ layer on Au(111): the role of out-of-plane atomic displacement

Abstract

Here, we show that the electronic properties of a surface-supported 2-dimensional (2D) layer structure can self-texturize at nanoscale. The local electronic properties are determined by structural relaxation processes through variable adsorption stacking configurations. We demonstrate that the spatially modulated layer-buckling, which arises from the lattice mismatch and the layer/substrate coupling at the GdAu/Au(111) interface, is sufficient to locally open an energy gap of ∼0.5 eV at the Fermi level in an otherwise metallic layer. Additionally, this out-of-plane displacement of the Gd atoms patterns the character of the hybridized Gd-d states and shifts the center of mass of the Gd 4f multiplet proportionally to the lattice distortion. These findings demonstrate the close correlation between the electronic properties of the 2D-layer and its planarity. We demonstrate that the resulting template shows different chemical reactivities which may find important applications.

Influence of 4f filling on electronic and magnetic properties of rare earth-Au surface compounds

“…This indeed is the simple expectation for the larger ionic radius of the divalent Yb. However, the effect is very small and may also arise due to other important factors, such as the out-ofplane relaxation of the RE sublattice 34 , similar to that observed in Rashba type systems 35 .…”

Atomic and mesoscopic structure of Dy-based surface alloys on noble metals

“…In both cases, the observation of the moiré pattern points out to a different density of atoms in the first and second layers of the crystal. Correa et al reported the observation of different contrast moiré patterns in GdAu 2 [26]. Their theoretical results reveal the origin of the contrast to be various degrees of vertical relaxation of the alloy layer from the supporting substrate to form lattice-matched periodicity.…”

Two-Dimensional Rare Earth–Gold Intermetallic Compounds on Au(111) by Surface Alloying

“…9,10 The lattice mismatches in these systems results in periodically modulated moiré structures, leading to electronic modulations in these systems. 11,12 The structurally robust moiré lattices in GdAu2 has been reported as templates for well-aligned organic nanowires, 6 and dense arrays of Co nanodots. [13][14][15] In addition, two-dimensional ferromagnetic orders have been reported in these systems mainly originated from the 4f electrons in the rare earth atoms.…”

“…Lanthanide rare earth-based intermetallic compounds on noble metal surfaces are good examples of periodically modulated surfaces by surface alloying. Deposition of gadolinium (Gd) on hot Au(111) or Ag(111) gives rise to the formation of long-range ordered GdAu 2 and GdAg 2 . , The lattice mismatches in these systems results in periodically modulated moiré structures, leading to electronic modulations in these systems. , The structurally robust moiré lattices in GdAu 2 have been reported as templates for well-aligned organic nanowires and dense arrays of Co nanodots. − In addition, two-dimensional ferromagnetic orders have been reported in these systems mainly originating from the 4 f electrons in the rare earth atoms. , The Curie temperatures are ∼10 K and ∼80 K for GdAu 2 and GdAg 2 , respectively. Further, the reduced dimensionality gives rise to new exotic states in these systems.…”