Communications in Physics

The transformation of ferromagnetic properties of Fe3O4 into ferromagnetic properties of \(\alpha\)-Fe\(_2\)O\(_3\) by the polyol process, heat treatment, isothermally annealing and sintering

2024-07-15T10:58:38+07:00

In our present research, we have presented research on synthesizing micro/nanosized Fe₃O₄ (magnetite-type) by the polyol process, heat treatment, annealing and sintering processes. The structural change of the above material from low temperature to high temperature, the magnetic change of ferromagnetism of Fe₃O₄ into ferromagnetism of α-Fe₂O₃when the as-prepared samples of Fe₃O₄ and α-Fe₂O₃oxides are isothermally treated from low temperature to high temperature. Finally, it is experimentally confirmed that a significant structural change of magnetite-type micro/nanosized Fe₃O₄ oxides into the structure of hematite-type micro/nanosized α-Fe₂O₃oxides (hematite-type).

Structural prediction of carbon cluster isomers with machine-learning potential

2024-05-11T01:07:11+07:00

Structural prediction of low-energy isomers of carbon twelve-atom clusters is carried out using the recently developed machine-learning potential GAP-20. The GAP-20 agrees with density-functional theory calculations regarding geometric structures and average C-C bond lengths for most isomers. However, the GAP-20 substantially lowers the energies of cage-like structures, resulting in a wrong ground state. A comparison of the cohesive energies with the density-functional theory points out that the GAP-20 only gives good results for monocyclic rings. Two multicyclic rings appear as new low-energy isomers, which have yet to be discovered in previous research.

Hybridization of an s-wave impurity with graphene lattice

2024-06-11T15:55:31+07:00

Hybridization function is a quantity characterizing electron hoppings between an impurity and a host material in which the impurity resides, a full understandinging of it is crucial for studying correlation effects in various impurity problems. This work studies the hybridization function for the Anderson impurity model describing a single-orbital impurity on a honeycomb lattice simulating graphene and presents a calculation approach to obtain this function at low energy. Within this approach, the general form of the hybridization function in graphene is presented and analytical expressions of low-energy hybridization spectrum are obtained. The results quantitatively match numerical solutions for different impurity positions on the lattice. The effect of the low-energy hybridization spectrum and the capability to predict the correlated effects of the impurity problem are discussed thoroughly, suggesting that different types of pseudogap Kondo effect may occur at different impurity positions.