First-Principles Investigations of Chirality in Trimetallic Alloy Clusters: AlMnAu_n (n = 1–7)

Abstract

Chirality, also called handedness, plays a crucial role in function ranging from biological self-assembly schemes, organic polymer functionalities, to optical material designs. In this Article, we demonstrated a first-principles investigation of chirality in magnetic AlMnAun(0/+1/-1) (n = 1-7) clusters. Optimized structures of the AlMnAun clusters exhibit configurational combinations between AlAun+1 and MnAun+1 clusters, indicating a subtle but equal competition between Au-Al and Au-Mn interactions in the alloy clusters. High magnetic moments are equal to or greater than 4μB in AlMnAun clusters due to the presence of the Mn dopant. Chirality turns up with the forms of right-handed and left-handed in stable AlMnAu5, AlMnAu6, and AlMnAu7 clusters. As a result, reflection symmetries are found in vibrational Raman and circular dichroism spectra of these chiral pairs. The present study shows that chiral magnetic clusters can be composed by doping two heteroatoms with one intrinsic magnetic dopant into small gold clusters.

Iron doped gold cluster nanomagnets: ab initio determination of barriers for demagnetization

“…The face substituted system is most stable, followed by the edge (0.25 eV higher) and corner (0.64 eV higher) substitutions. The same result is found in the study of Tam et al 12 In Table 2, we further list the relative energies of the NEVPT2 calculations, using (c)-CAS (11,10), which support the energetic order of the B3LYP calculations. For most systems however, NEVPT2 predicts slightly higher relative energies.…”

“…[2][3][4][5][6][7] Gold clusters usually exhibit small (S ¼ 0, 1/2) spin quantum numbers, leading to closed shell or doublet electronic ground states but doping them with a transition metal atom can lead to open-shell clusters with signicantly higher spin-quantum numbers. [8][9][10][11][12][13][14] For example, Tam et al 12 investigated the structure and stability of transition metal doped golden pyramids Au 19 M (M ¼ Cr, Mn, Fe) at the level of generalized gradient density functional theory (DFT). All systems show higher ground state spin quantum numbers, while the structural modications are minor.…”

“…Several studies have investigated transition metal doped gold clusters using DFT. [8][9][10][11][12][13][14] These studies focused on predicting stable structures and their spin quantum numbers. On the other hand, several studies examined magnetic properties of transition metal complexes, i.e., a transition metal ion surrounded by a primarily organic framework, with wave function based, multireference perturbation theory methods.…”

“…We conclude that larger active spaces are necessary to appropriately describe the odd electron count system. The active space (c)-CAS (11,10) is sufficiently large while still computationally feasible and will therefore be used for further investigations. In addition, we will compare the results to calculations of the second "d-only" (f)-CAS (7,5) approach.…”

Introducing Magnetism into 2D Nonmagnetic Inorganic Layered Crystals: A Brief Review from First-Principles Aspects

“…When clusters or atoms contact the substrate, physical or chemical adsorptions occur due to the interaction schemes and kinetic energies of the 0D objects [49]. Along with tailored optic and electronic properties [50], the guest clusters are endowed with tunable magnetism and chemical reactivity [51,52], which allows them to act as essential building bricks for functional nanomaterials [53]. A previous doping strategy showed that replacing both the Mo and S atoms with FeX 6 (X = S, C, N, O, F) clusters allowed for intrinsic ferromagnetism to be brought into the cluster-doped stable slabs [54].…”