A DFT Assessment on the Structural, Thermodynamic, and Electrical Properties of Transition Metal‐Doped Gallium Arsenide Nanoclusters (Ga n As n , Where n = 4, 5, and 6)

In the era of nanotechnology, a wide range of theoretical and experimental research has been performed on different aluminum nitride nanotubes for their great acceptance in advanced technology and biomedical applications. In this work, the structural, thermodynamic, electrical, magnetic and optical properties of aluminum nitride nanotubes (AlNNT) have been investigated before and after doping them individually with transition metals (TM), Cr and Mo. From the analysis of electronic properties, it has been observed that the doping transition metal with pristine Al[Formula: see text]N[Formula: see text] nanotube causes a significant increase in the electrical conductivity of the nanotubes, which signifies their potential to be used in optoelectronic devices and solar cells. According to the study of thermodynamic properties, doping of TMs causes more stability in a pristine structure. Moreover, from the study of IR spectroscopy, no imaginary frequency has been observed for any of the pristine and TM-doped aluminum nitride nanotubes, which signifies that all nanotubes will form true energy minima and the most stable state. According to the DOS analysis, the TM-doped nanotubes show splitting of their molecular orbitals, indicating their potential for use in spintronic devices. All calculations in this study were obtained by employing the density functional theory (DFT) with B3LYP hybrid exchange correlational functional using the LanL2DZ basis set. The doping was done by replacing an Al or [Formula: see text] atom from the nanotube with Cr or Mo, thus forming four nanotubes. The pristine and the doped nanotubes were optimized to the minimum ground state energy of their corresponding structure to obtain maximum structural stability.

First-principles study of adsorption of 3d and 4d transition metal atoms on aluminene

Graphene, which is accepted as the main material of nanomaterials, attracts great attention thanks to its applicability in almost every field and its superior properties. The zero-band graphene gap is a problem that scientists must overcome in designing new electronics. Tailoring the electronic properties of graphene systems by making a change in the band gap allow us great advantages. In this study, Intercalation of transition metal (TM) atom to graphene systems as sandwich-like graphene|TM|graphene structures were investigated by ab initio first principle Density Functional Theory (DFT) computations. GGA with BPW91 basis set were used for DFT calculations. DFT calculations were performed on W, Re, and Os transition metal atoms intercalted between bilayer graphene (BLG). After geometry optimization of graphene|TM|graphene structures, graphene layers doped with nitrogen atoms by substitutional doping for investigation of change in electronic behavior. The electronic behaviour of metal intercalated BLG structures can be modified by type of transition metal and dopant as a result of charge transfer. Substitutional doping with nitrogen atoms to graphene structures showed a change in local density due to the charge transfer as a result of its extra one electron. Placing a transition metal atom between BLG layers leads to constriction in the band gap with a boost in conductive character.

The structural, electronic, and magnetic properties of 3d transition metal (TM) atoms (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) adsorbed germanene are addressed using density functional theory. Based on the adsorption energy, TM atoms prefer to occupy at the hollow site for all the cases. The obtained values of the total magnetic moment vary from 0.97 to 4.95 μB in the case of Sc to Mn adsorption, respectively. A gap of 74 meV with a strongly enhanced splitting of 67 meV is obtained in case of Sc adsorption, whereas metallic states are obtained in case of Ti, Cr, Mn, Fe, and Co. Nonmagnetic states are realized for Ni, Cu, and Zn adsorption. Moreover, semiconducting nature is obtained for nonmagnetic cases with a gap of 26–28 meV. Importantly, it is found that V-adsorbed germanene can host the quantum anomalous Hall effect. The obtained results demonstrate that TM atoms and nearest-neighbor Ge atoms are ferromagnetically ordered in the cases of V, Mn, Fe, Co, Ni, Cu, and Zn, while antiferromagnetic ordering is obtained for Sc, Ti, and Cr. In addition, the effects of the coverage of all TM atoms on the electronic structure and the ferromagnetic and antiferromagnetic coupling in the case of Mn are examined. The results could help to understand the effect of TM atoms in a new class of two-dimensional materials beyond graphene and silicene.

Density functional theory calculations have been carried out to investigate 3d, Pd and Pt transition metal (TM) atoms exohedrally and endohedrally doped B 80 fullerene. We find that the most preferred doping site of the TM atom gradually moves from the outer surface ( TM = Sc ), to the inner surface ( TM = Ti and V ) and the center ( TM = Cr , Mn , Fe and Zn ), then to the outer surface ( TM = Co , Ni , Cu , Pd , and Pt ) again with the TM atom varying from Sc to Pt . From the formation energy calculations, we find that doping TM atom can further improve the stability of B 80 fullerene. The magnetic moments of doped V , Cr , Mn , Fe , Co and Ni atoms are reduced from their free-atom values and other TM atoms are completely quenched. Charge transfer and hybridization between 4s and 3d states of TM and 2s and 2p states of B were observed. The energy gaps of TM @ B 80 are usually smaller than that of the pure B 80. Endohedrally doped B 80 fullerene with two Mn and two Fe atoms were also considered, respectively. It is found that the antiferromagnetic (AFM) state is more energetically favorable than the ferromagnetic (FM) state for Mn 2- and Fe 2@ B 80. The Mn and Fe atoms carry the residual magnetic moments of ~ 3 μB and 2 μB in the AFM states.

'The specific aim of this report is to parameterize force field to reproduce geometries and relative energetics of metal-ligand complexes for cesium, strontium, plutonium, uranium, americium and other relevent alkali, transition, lanthanide and actinide metals. As an initial attempt to examine parametrization, Dr. Yasuo Takeuchi has examined parameters for iron in combination with the molecular mechanics force field. The authors realize that most of the current ad hoc methodogies used to model metal interactions in the past do not have a firm theoretical foundation for modeling the d and f orbitals. They have, therefore, started a collaboration with Prof. Anders Carlsson of the Department of Physics to provide a theoretically correct functional form for the metal force field. Prof. Carlsson has an extensive track record in the derivation of the form of angular force fields from analysis of the quantum-mechanical electronic structure. His most important related works have treated the angular forces around transition-metal (TM) atoms in an aluminum host, the angular forces in elemental bcc transition metals, and the origins of angular and torsional forces in well-bonded s-p systems. They propose to apply the basic ideas of these calculations to developing force laws for transition metal ions in biomolecules. Of particular relevance to the proposed work is his study analyzing angular forces around transition metal (TM) atoms embedded in an aluminum host. Such TM atoms have a profound effect on the host structure, often entirely reassembling the host structure in order to satisfy the angular bonding constraints around the TM atoms. For example, at a concentration of only 1 {approximately} TM to 12 {approximately} Al, the transition metals Mn, Mo, Tc, W, and Re form the Al{sup 12}W structure, in which the underlying fcc aluminum lattice is disassembled and reassembled into icosahedra which surround the transition-metal atoms. The Al{sup 12}W structure is a body-centered cubic arrangement of such icosahedra. This behavior is analogous to that of several transition metals in proteins and other potential hosts, for example the formation of square-planar or Jahn-teller distorted octahedral structure by Cu{sup 2+} ions in many proteins. In both cases, the transition metal atom or ion has strong preferences regarding its angular environment. Of course, other effects, such as steric constraints on the ligands, are also important and dominate in some cases.'

Effects of transition metal intercalation on the electronic and magnetic properties of CrI3/WSe2 heterostructure

Electronic properties of transition metal embedded twin T-graphene: A density functional theory study

Searching for high-activity, stable and low-cost catalysts toward oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are of significant importance to the development of renewable energy technologies. By using the computational screening method based on the density functional theory (DFT), we have systematically studied a wide range of transition metal (TM) atoms doped a defective BC3 monolayer (B atom vacancy VB and C atom vacancy VC), denoted as TM@VB and TM@VC (TM = Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ir and Pt), as efficient single atom catalysts for OER and ORR. The calculated results show that all the considered TM atoms can tightly bind with the defective BC3 monolayers to prevent the atomically dispersed atoms from clustering. The interaction strength between intermediates (HO*, O* and HOO*) and catalyst govern the catalytic activities of OER and ORR, which has a direct correlation with the d-band center (εd) of the TM active site that can be tuned by adjusting TM atoms with various d electron numbers. For TM@VB catalysts, it was found that the best catalyst for OER is Co@VB with an overpotential ηOER of 0.43 V, followed by Rh@VB (ηOER = 0.49 V), while for ORR, Rh@VB exhibits the lowest overpotential ηORR of 0.40 V, followed by Pd@VB (ηORR = 0.45 V). For TM@VC catalysts, the best catalyst for OER is Ni@VC (ηOER = 0.47 V), followed by Pt@VC (ηOER = 0.53 V), and for ORR, Pd@VC exhibits the highest activity with ηORR of 0.45 V. The results suggest that the high activity of the newly predicted well dispersed Rh@VB SAC is comparable to that of noble metal oxide benchmark catalysts for both OER and ORR. Importantly, Rh@VB may remain stable against dissolution at pH = 0 condition. The high energy barrier prevents the isolated Rh atom from clustering and ab initio molecule dynamic simulation (AIMD) result suggests that Rh@VB can remain stable under 300 K, indicating its kinetic stability. Our findings highlight a novel family of efficient and stable SAC based on carbon material, which offer a useful guideline to screen the metal active site for catalyst designation.

Effects of interstitial dopings of 3d transition metal atoms on antimonene: A first-principles study

First principles insights into the electronic and magnetic properties of [formula omitted] doped with VIII-group transition metal single atom

Adsorption of 3d transition-metal atom on InSe monolayer: A first-principles study

Using the first-principles plane-wave pseudopotential method within density functional theory, we have systematically investigated structural, electronic, and mechanical properties of , (; ; and ) nanowires and bulk phase of . We found that not only , but also transition metal and chalcogen atoms lying in the same columns of Mo and Se can form stable nanowires consisting of staggered triangles of . We have shown that all wires have nonmagnetic ground states in their equilibrium geometry. Furthermore, these structures can be either a metal or semiconductor depending on the type of chalcogen element. All wires with atom are semiconductors. Mechanical stability, elastic stiffness constants, breaking point, and breaking force of these wires have been calculated in order to investigate the strength of these wires. molecular dynamic simulations performed at suggest that overall structure remains unchanged at high temperature. Adsorption of H, O, and transition metal atoms like Cr and Ti on have been investigated for possible functionalization. All these elements interact with wire forming strong chemisorption bonds, and a permanent magnetic moment is induced upon the adsorption of Cr or Ti atoms. Molybdenum selenide-type nanowires can be alternative for carbon nanotubes, since the crystalline ropes consisting of one type of structures can be decomposed into individual nanowires by using solvents, and an individual nanowire by itself is either a metal or semiconductor and can be functionalized.

We have systematically investigated the growth behavior and stability of small stoichiometric (TiO2)n (n = 1–10) clusters as well as their structural, electronic and magnetic properties by using the first-principles plane wave pseudopotential method within density functional theory. In order to find out the ground state geometries, a large number of initial cluster structures for each n has been searched via total energy calculations. Generally, the ground state structures for the case of n = 1–9 clusters have at least one monovalent O atom, which only binds to a single Ti atom. However, the most stable structure of the n = 10 cluster does not have any monovalent O atom. On the other hand, Ti atoms are at least fourfold coordinated for the ground state structures for n ≥ 4 clusters. Our calculations have revealed that clusters prefer to form three-dimensional structures. Furthermore, all these stoichiometric clusters have nonmagnetic ground state. The formation energy and the highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap for the most stable structure of (TiO2)n clusters for each n have also been calculated. The formation energy and hence the stability increases as the cluster size grows. In addition, the interactions between the ground state structure of the (TiO2)n cluster and a single water molecule have been studied. The binding energy (Eb) of the H2O molecule exhibits an oscillatory behavior with the size of the clusters. A single water molecule preferably binds to the cluster Ti atom through its oxygen atom, resulting an average binding energy of 1.1 eV. We have also reported the interaction of the selected clusters (n = 3, 4, 10) with multiple water molecules. We have found that additional water molecules lead to a decrease in the binding energy of these molecules to the (TiO2)n clusters. Finally, the adsorption of transition metal (TM) atoms (V, Co and Pt) on the n = 10 cluster has been investigated for possible functionalization. All these elements interact strongly with this cluster, and a permanent magnetic moment is induced upon adsorption of Co and V atoms. We have observed gap localized TM states leading to significant HOMO–LUMO gap narrowing, which is essential to achieve visible light response for the efficient use of TiO2 based materials. In this way, electronic and optical as well as magnetic properties of TiO2 materials can be modulated by using the appropriate adsorbate atoms.

Anchoring transition metal (TM) atoms on suitable substrates to form single-atom catalysts (SACs) is a novel approach to constructing electrocatalysts. Graphdiyne with sp-sp2 hybridized carbon atoms and uniformly distributed pores have been considered as a potential carbon material for supporting metal atoms in a variety of catalytic processes. Herein, density functional theory (DFT) calculations were performed to study the single TM atom anchoring on graphdiyne (TM1 -GDY, TM=Sc, Ti, V, Cr, Mn, Co and Cu) as the catalysts for CO2 reduction. After anchoring metal atoms on GDY, the catalytic activity of TM1 -GDY (TM=Mn, Co and Cu) for CO2 reduction reaction (CO2 RR) are significantly improved comparing with the pristine GDY. Among the studied TM1 -GDY, Cu1 -GDY shows excellent electrocatalytic activity for CO2 reduction for which the product is HCOOH and the limiting potential (UL ) is -0.16 V. Mn1 -GDY and Co1 -GDY exhibit superior catalytic selectivity for CO2 reduction to CH4 with UL of -0.62 and -0.34 V, respectively. The hydrogen evolution reaction (HER) by TM1 -GDY (TM=Mn, Co and Cu) occurs on carbon atoms, while the active sites of CO2 RR are the transition metal atoms . The present work is expected to provide a solid theoretical basis for CO2 conversion into valuable hydrocarbons.