In this work, we systematically studied the structure, and electronic and magnetic properties of van der Waals (vdWs) interface Graphene/MoS₂ heterostructure (HS-G/MoS₂) and C sites vacancy defects in HS-G/MoS₂ materials using first-principles calculations. By the structural analysis, we found that nondefects geometry is more compact than defects geometries. To investigate the electronic and magnetic properties of HS-G/MoS₂ and C sites vacancy defects in HS-G/MoS₂ materials, we have studied band structure, density of states (DOS), and partial density of states (PDOS). By analyzing the results, we found that HS-G/MoS₂ is metallic in nature but C sites vacancy defects in HS-G/MoS₂ materials have a certain energy bandgap. Also, from the band structure calculations, we found that Fermi energy level shifted towards the conduction band in vacancy defects geometries which reveals that the defected heterostructure is n-type Schottky contacts. From DOS and PDOS analysis, we obtained that the nonmagnetic HS-G/MoS₂ material changes to magnetic materials due to the presence of C sites vacancy defects. Right 1C atom vacancy defects (R-1C), left 1C atom vacancy defects (L-1C), centre 1C atom vacancy defects (C-1C), and 2C (1C right and 1C centre) atom vacancy defects in HS-G/MoS₂ materials have magnetic moments of 0.75 µ_B/cell, 0.75 µ_B/cell, 0.12 µ_B/cell, and +0.39 µ_B/cell, respectively. Electrons from 2s and 2p orbitals of C atoms have main contributions for the magnetism in all these materials.

MAX phase compounds have a unique blend of ceramic and metallic properties and have been established as promising materials for device applications. In the present work, we have investigated the structural, dynamical, mechanical, electronic, magnetic, and optical properties of Ti₂CdC and Ti₂SC MAX phase compounds using a density functional theory approach through the Vienna Ab initio Simulation Package. The structural, dynamical, and mechanical properties of both MAX phase compounds are studied and found to be stable. Additionally, the mechanical properties reveal that both compounds have hardness and a crystalline anisotropic, bond-stretching, and brittle nature. From the analysis of elastic anisotropy calculations, it is found that Ti₂CdC has metallic-like bonding, while Ti₂SC has covalent-like bonding. The electronic and magnetic properties of the Ti₂CdC and Ti₂SC compounds are determined, and it is found that they have metallic and non-magnetic properties for the generalized gradient approximation (GGA): Perdew–Burke–Ernzerh (PBE) functional, whereas they have metallic and magnetic properties for the GGA: PBE + U functional(U is Hubbard parameter). We have explored the optical properties of the considered materials and found that they have compelling interactions with electromagnetic radiation, notable values of absorption energy, that less transparency occurred at the lower energy region, and that they have high thermal properties. Based on the major findings of the above considered materials, Ti₂CdC and Ti₂SC can be used in the fields of optoelectronic devices, sensors, advanced photonic devices, infrared imaging, solar thermal collectors, thermal insulation, nuclear devices, and energy dissipation devices.

First-principle calculations based on the spin-polarized density functional theory (DFT) with vdW corrections by DFT-D2 approach have been carried out to study structural, electronic, and magnetic properties of water-adsorbed graphene/MoS₂ heterostructures (system-I), and water-adsorbed graphene/MoS₂ heterostructures with vacancy defects in Mo sites (systems-II). We consider vacancy defects in different Mo sites such as centre-1Mo atom vacancy defect (system-IIa), left-1Mo atom vacancy defect (system-IIb), and 2Mo atom vacancy defects (system-IIc). All the systems considered in this study are structurally stable; however, the stability of defected systems decreases with an increase in defect concentrations. The calculated binding energies of HS used in this study agree with the reported work. Electronic properties of system-I and systems-II reveal that they have metallic characteristics. Our investigation shows that system-I is nonmagnetic and systems-II are magnetic. The magnetic moment in the defected systems (system-IIa, system-IIb, and system-IIc) is developed by unpaired up and down-spins of electrons created in the orbitals of atoms due to vacancy defects in Mo atoms.

Recent years have seen a great deal of excitement in the study of the structural, electronic and magnetic behavior of two-dimensional (2D) materials. This has great promise for improved electronics, fascinating quantum technologies, and energy-efficient gadgets. In the current work, we have investigated the structural, electronic, and magnetic properties of bilayer h-BN and water adsorption on pristine h-BN bilayer supercell material using the density functional theory (DFT) method. We have examined the structural properties, and found that they are structurally stable materials. We have examined the band structure and density of states (DoS) calculations of h-BN, and water adsorbed h-BN materials. It is found that water adsorbed on pure h-BN is an n-type Schottky semiconducting material, and pristine h-BN is a broad bandgap p-type Schottky material. P-type insulating material becomes n-type semiconducting material when water molecules are adsorbed. Additionally, after looking the materials' magnetic properties through their DoS and partial density of states (PDoS) analysis. We found that h-BN, and water adsorbed h-BN have non-magnetic properties. Thus, they have been employed extensively in many different industries because of their bandgap energy and non-magnetic in nature.

In this work, we have studied the electronic and magnetic properties of 1C atom vacancy defects in graphene (1C_v-d-G), 1N atom impurity defects in graphene (1N_I-d-G) and 1O atom impurity defects in graphene (1O_I-d-G) materials through first principles calculations based on spin-polarized density functional theory (DFT) method, using computational tool Quantum ESPRESSO (QE) code. From band structure and density of states (DOS) calculations, we found that supercell structure of monolayer graphene is a zero bandgap material. But, electronic bands of 1C_v-d-G, 1N_I-d-G and 1O_I-d-G materials split around the Fermi energy level and DOS of up & down spins states appear in the Fermi energy level. Thus, 1C_v-d-G, 1N_I-d-G and 1O_I-d-G materials have metallic properties. We have studied the magnetic properties of pure and defected materials by analyzing density of states (DOS) and partial density of states (PDOS) calculations. We found that graphene and 1O_I-d-G materials have non-magnetic properties. On the other hand, 1C vacancy atom and 1N impurity atom induced magnetization in 1C_v-d-G & 1N_I-d-G materials by the rebonding of dangling bonds and acquiring significant magnetic moments of values -0.75μ_B/cell & 0.05μ_B/cell respectively through remaining unsaturated dangling bond. Therefore, non-magnetic graphene changes to magnetic 1C_v-d-G and 1N_I-d-G materials due to 1C atom vacancy defects and 1N atom impurity defects. The 2p orbital of carbon atoms has main contribution of magnetic moment in these defected structures.