Structural, electronic and magnetic properties of S sites vacancy defects graphene/MoS2 van der Waals heterostructures: First-principles study

In this work, we investigated the geometrical structures, electronic and magnetic properties of S sites vacancy defects in heterostructure graphene/molybdenum disulphide ((HS)G/MoS[Formula: see text] material by performing first-principles calculations based on spin polarized Density Functional Theory (DFT) method within van der Waals (vdW) corrections (DFT-D2) approach. All the structures are optimized and relaxed by BFGS method using computational tool Quantum ESPRESSO (QE) package. We found that both (HS)G/MoS2 and S sites vacancy defects in (HS)G/MoS2 (D1S–(HS)G/MoS2, U1S–(HS)G/MoS2, 2S–(HS)G/MoS2 and 3S–(HS)G/MoS[Formula: see text] are stable materials, and atoms in defects structures are more compact than in pristine (HS)G/MoS2 structure. From band structure calculations, we found that (HS)G/MoS2, (D1S–(HS)G/MoS2, U1S–(HS)G/MoS2, 2S–(HS)G/MoS2 and 3S–(HS)G/MoS[Formula: see text] materials have [Formula: see text]-type Schottky contact. The Dirac cone is formed in conduction band of the materials mentioned above. The barrier height of Dirac cones from Fermi energy level of (HS)G/MoS2, (D1S–(HS)G/MoS2, U1S–(HS)G/MoS2, 2S–(HS)G/MoS2 and 3S–(HS)G/MoS[Formula: see text] materials have values 0.56[Formula: see text]eV, 0.62[Formula: see text]eV, 0.62[Formula: see text]eV, 0.64[Formula: see text]eV and 0.65[Formula: see text]eV, respectively, which means they have metallic properties. To study the magnetic properties of materials, we have carried out DoS and PDoS calculations. We found that (HS)G/MoS2, D1S–(HS)G/MoS2 and U1S–(HS)G/MoS2 materials have non-magnetic properties, and 2S–(HS)G/MoS2 and 3S–(HS)G/MoS2 materials have magnetic properties. Therefore, the non-magnetic (HS)G/MoS2 changes to magnetic 2S–(HS)G/MoS2 and 3S–(HS)G/MoS2 materials due to 2S and 3S atoms vacancy defects, respectively, in (HS)G/MoS2 material. Magnetic moment obtained in 2S–(HS)G/MoS2 and 3S–(HS)G/MoS2 materials due to the unequal distribution of up and down spin states of electrons in 2s and 2p orbitals of C atoms; 4p, 4d and 5s orbitals of Mo atoms; and 3s and 3p orbitals of S atoms in structures. Magnetic moment of 2S–(HS)G/MoS2 and 3S–(HS)G/MoS2 materials is −0.11[Formula: see text][Formula: see text]/cell and [Formula: see text]/cell, respectively, and spins of 2p orbital of C atoms, 3p orbital of S atoms and 4d orbital of Mo atoms have dominant role to create magnetism in 2S–(HS)G/MoS2 and 3S–(HS)G/MoS2 materials.

Tunable electronic structure and magnetic moment in C2N nanoribbons with different edge functionalization atoms

Physical Chemistry Chemical Physics ◽

10.1039/c7cp01359k ◽

2017 ◽

Vol 19 (23) ◽

pp. 15021-15029 ◽

Cited By ~ 7

Author(s):

Yusheng Wang ◽

Nahong Song ◽

Min Jia ◽

Dapeng Yang ◽

Chikowore Panashe ◽

...

Keyword(s):

Magnetic Properties ◽

Electronic Structure ◽

Magnetic Moment ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Functional Theory ◽

First principles calculations based on density functional theory were carried out to study the electronic and magnetic properties of C2N nanoribbons (C2NNRs).

First-principles study of structure, electronic, and magnetic properties of C sites vacancy defects in water adsorbed graphene/MoS2 van der Waals heterostructures

Journal of Molecular Modeling ◽

10.1007/s00894-021-04690-8 ◽

2021 ◽

Vol 27 (3) ◽

Author(s):

Hari Krishna Neupane ◽

Narayan Prasad Adhikari

Keyword(s):

Magnetic Properties ◽

First Principles ◽

Van Der Waals ◽

Van Der Waals Heterostructures ◽

Vacancy Defects ◽

First Principles Study

First-principles study of C cites vacancy defects in water adsorbed Graphene

Himalayan Physics ◽

10.3126/hp.v9i01.40150 ◽

2020 ◽

pp. 19-29

Author(s):

Hari Krishna Neupane ◽

Narayan Prasad Adhikari

Keyword(s):

Magnetic Properties ◽

Band Gap ◽

Density Of States ◽

Magnetic Moment ◽

First Principles ◽

Density Functional ◽

Partial Density ◽

Dangling Bonds ◽

Graphene Surface ◽

Vacancy Defects

The electronic and magnetic properties of water adsorbed graphene (wad – G), single carbon (1C) atom vacancy defects in water adsorbed graphene (1Catom-vacancy – wad – G) and double carbon (2C) atoms vacancy defects in water adsorbed graphene (2Catom-vacancy – wad – G) materials are studied by ﬁrst-principles calculations within the frame work of density functional theory (DFT) using computational tool Quantum ESPRESSO (QE) code. We have calculated the binding energy of wad – G, 1Catom-vacancy – wad – G and 2Catom-vacancy – wad – G materials, and then found that non-defects geometry is more compact than vacancy defects geometries. From band structure calculations, we found that wad – G is zero band gap semiconductor, but 1Catom-vacancy – wad – G and, 2Catom-vacancy – wad – G materials have metallic properties. Hence, zero band gap semiconductor changes to metallic nature due to C sites vacancy defects in its structures. We have investigated the magnetic properties of wad – G and its C sites vacancy defects materials by using Density of States (DOS) and Partial Density of States (PDOS) calculations. We found that wad – G is non- magnetic material. 1C atom vacancy defects in graphene surface of wad – G is induced magnetization by the re-bonding of two dangling bonds and acquiring signiﬁcant magnetic moment (0.11 µB/ cell) through remaining unsaturated dangling bond. But, 2C atoms vacancy defects in graphene surface of wad – G induced low value of magnetic moment (+0.03 µB/ cell) than 1C atom vacancy defects in structure, which is due to no dangling bonds present in the structure. Therefore, non-magnetic, wad – G changes to magnetic, 1Catom-vacancy – wad – G and, 2Catom-vacancy – wad – G materials due to C sites vacancy defects in wad – G structure. The 2p orbital of carbon atoms has main contribution of magnetic moment in defects structures.

First Principles Investigations on the Electronic and Magnetic Properties of La4Ba2Cu2O10

Journal of Nepal Physical Society ◽

10.3126/jnphyssoc.v3i1.14448 ◽

2016 ◽

Vol 3 (1) ◽

pp. 89 ◽

Cited By ~ 1

Author(s):

Shalika Ram Bhandari ◽

Ram Kumar Thapa ◽

Madhav Prasad Ghimire

Keyword(s):

Magnetic Properties ◽

Charge Transfer ◽

Magnetic Moment ◽

Ground State ◽

First Principles ◽

Density Functional ◽

Dft Calculation ◽

Functional Theory ◽

Electronic and magnetic properties of La4Ba2Cu2O10 had been studied by first-principles density functional theory (DFT). Based on the DFT calculation La4Ba2Cu2O10 is found to have a ferromagnetic (FM) ground state. The material undergo charge-transfer type insulator to Mott-Hubbard type insulator transition which happens due to strong correlation in La-4f and Cu-3d states. Our results show that the 3d electrons of Cu hybridize strongly with O-2p states near the Fermi level giving rise to the insulating state of La4Ba2Cu2O10. Our study suggests that the enhanced magnetic moment is a result of itinerant exchange rather than the exchange interaction involving individual ions of Cu atoms. The total magnetic moment calculated in the present studies is 2 μB per unit cell for La4Ba2Cu2O10.Journal of Nepal Physical Society Vol.3(1) 2015: 89-96

Electronic and magnetic properties of defected MoS2 monolayer

BIBECHANA ◽

10.3126/bibechana.v18i2.33905 ◽

2021 ◽

Vol 18 (2) ◽

pp. 68-79

Author(s):

Hari Krishna Neupane ◽

Narayan Prasad Adhikari

Keyword(s):

Magnetic Properties ◽

Magnetic Moment ◽

Density Functional ◽

2D Materials ◽

Dft Method ◽

Vacancy Defect ◽

Energy Bands ◽

Band Structures ◽

Vacancy Defects ◽

It is interesting to understand the effect of defects in 2D materials because vacancy defects in 2D materials have novel electronic and magnetic properties. In this work, we studied electronic and magnetic properties of 1S vacancy defect (1Sv-MoS2), 2S vacancy defects (2Sv-MoS2), 1Mo vacancy defect (Mov-MoS2), and (1Mo & 1S) vacancy defects ((Mo-S)v-MoS2) in 2D MoS2 material by first-principles calculations within spin-polarized density functional theory (DFT) method. To understand the electronic properties of materials, we have analyzed band structures and DOS calculations and found that 1Sv-MoS2 & 2Sv-MoS2 materials have semiconducting nature. This is because, 1Sv-MoS2 & 2Sv-MoS2 materials open a small energy band gap of values 0.68 eV & 0.54 eV respectively in band structures. But, in Mov-MoS2 & (Mo-S)v-MoS2 materials, energy bands around the Fermi level mix with the orbital’s of Mo and S atoms. As a result, bands are split and raised around and above the Fermi energy level. Therefore, Mov-MoS2 & (Mo-S)v-MoS2 materials have metallic nature. We found that MoS2, 1Sv-MoS2 & 2Sv-MoS2 materials have non-magnetic properties, and Mov-MoS2 & (Mo-S)v-MoS2 materials have magnetic properties because magnetic moment of MoS2, 1Sv-MoS2 & 2Sv-MoS2 materials have 0.00 µB/cell value and Mov-MoS2 & (Mo-S)v-MoS2 materials have 2.72 µB/cell & 0.99 µB/cell respectively. Therefore, non-magnetic MoS2 changes to magnetic Mov-MoS2 & (Mo-S)v-MoS2 materials due to Mo and (1Mo & 1S) vacancy defects. The magnetic moment obtained in Mov-MoS2 & (Mo-S)v-MoS2 materials due to the distribution of up and down spins in 4p, 4d & 5s orbitals of Mo atoms and 3s & 3p orbitals of S atoms in structures. The significant values of the magnetic moment are given by distributed spins in 4d orbital of Mo atoms and 3p orbital of S atoms. BIBECHANA 18 (2) (2021) 68-79

Structural, Electronic and Magnetic Properties of Impurities Defected Graphene/MoS2 Van Der Waals Heterostructure: First-principles Study

Journal of Nepal Physical Society ◽

10.3126/jnphyssoc.v7i2.38578 ◽

2021 ◽

Vol 7 (2) ◽

pp. 1-8

Author(s):

H. K. Neupane ◽

N. P. Adhikari

Keyword(s):

Magnetic Properties ◽

Magnetic Moment ◽

Van Der Waals ◽

Schottky Contact ◽

Impurity Defect ◽

Spin Polarized ◽

Device Applications ◽

Properties Of Materials ◽

P Type

Two-dimensional (2D) pristine and defected van der Waals (vdW) heterostructure (HS) materials open up fortune in nanoelectronic and optoelectronic devices. So, they are compatible for designing in the fields of device applications. In the present work, we studied structural, electronic and magnetic properties of vdW (HS) graphene/MoS2 ((HS)G/MoS2), Nb impurity defect in vdW (HS) graphene/MoS2 (Nb-(HS)G/MoS2), and Tc impurity defect in vdW (HS) graphene/MoS2 (Tc-(HS)G/MoS2) materials by using spin-polarized DFT-D2 method. We examined the structure of these materials, and found that they are stable. Based on band structure analysis, we found that (HS)G/MoS2, Nb-(HS)G/MoS2 and Tc-(HS)G/MoS2 have metallic characteristics. Also, (HS)G/MoS2 and Tc-(HS)G/MoS2 materials have n-type Schottky contact, while Nb-(HS)G/MoS2 material has p-type Schottky contact. To understand the magnetic properties of materials, we have used DoS, IDoS and PDoS calculations. We found that (HS)G/MoS2 is a non-magnetic material, but Nb-(HS)G/MoS2 and Tc-(HS)G/MoS2 are magnetic materials. Magnetic moment of Nb-(HS)G/MoS2 and Tc-(HS)G/MoS2 materials are -0.24 μB/cell and +0.07μB/cell values respectively from DoS/PDoS calculations, and 0.26 μB/cell and 0.08μB/cell values respectively from IDoS calculations. Up-spin and down-spin states of electrons in 2p orbital of C atoms, 3p orbital of S atoms, 4d orbital of Mo atoms, 4d orbital of Tc atom in Tc-(HS)G/MoS2, and 2p orbital of C atoms, 3p orbital of S atoms, 4p & 4d orbitals of Mo atoms, 4p & 4d orbitals of Nb atom in Nb-(HS)G/MoS2 have major contribution for the development of magnetic moment.

Tuning Structural, Electronic, and Magnetic Properties of C Sites Vacancy Defects in Graphene/MoS2 van der Waals Heterostructure Materials: A First-Principles Study

Advances in Condensed Matter Physics ◽

10.1155/2020/8850701 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Hari Krishna Neupane ◽

Narayan Prasad Adhikari

Keyword(s):

Magnetic Properties ◽

Band Structure ◽

Density Of States ◽

First Principles ◽

Magnetic Moments ◽

Van Der Waals ◽

Partial Density ◽

Vacancy Defects ◽

Structure Density

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 µB/cell, −0.75 µB/cell, −0.12 µB/cell, and +0.39 µB/cell, respectively. Electrons from 2s and 2p orbitals of C atoms have main contributions for the magnetism in all these materials.

Structural, Electronic and Magnetic Properties of Geometrically Frustrated Spinel CdCr2O4 from First-principles Based on Density Functional Theory

Journal of Material Science & Engineering ◽

10.4172/2169-0022.1000250 ◽

2016 ◽

Vol 5 (4) ◽

Cited By ~ 2

Author(s):

Bolandhemat N

Keyword(s):

Magnetic Properties ◽

First Principles ◽

Density Functional ◽

Functional Theory ◽

Geometrically Frustrated

Width-dependent structural stability and magnetic properties of monolayer zigzag MoS2 nanoribbons

Modern Physics Letters B ◽

10.1142/s0217984917500178 ◽

2017 ◽

Vol 31 (03) ◽

pp. 1750017 ◽

Cited By ~ 7

Author(s):

Yan-Ni Wen ◽

Peng-Fei Gao ◽

Xi Chen ◽

Ming-Gang Xia ◽

Yang Zhang ◽

...

Keyword(s):

Magnetic Properties ◽

Structural Stability ◽

Magnetic Moment ◽

First Principles ◽

Density Functional ◽

Electronic States ◽

Two Dimensional ◽

Functional Theory ◽

Proportional Relationship

First-principles study based on density functional theory has been employed to investigate width-dependent structural stability and magnetic properties of monolayer zigzag MoS2 nanoribbons (ZZ-MoS2 NRs). The width N = 4–6 (the numbers of zigzag Mo–S chains along the ribbon length) are considered. The results show that all studied ZZ-MoS2 NRs are less stable than two-dimensional MoS2 monolayer, exhibiting that a broader width ribbon behaves better structural stability and an inversely proportional relationship between the structural stability (or the ribbon with) and boundary S–Mo interaction. Electronic states imply that all ZZ-MoS2 NRs exhibit magnetic properties, regardless of their widths. Total magnetic moment increases with the increasing width N, which is mainly ascribed to the decreasing S–Mo interaction of the two zigzag edges. In order to confirm this reason, a uniaxial tension strain is applied to ZZ-MoS2 NRs. It has been found that, with the increasing tension strain, the bond length of boundary S–Mo increases, at the same time, the magnetic moment increases also. Our results suggest the rational applications of ZZ-MoS2 NRs in nanoelectronics and spintronics.

Tuning the electronic and magnetic properties of Mn-doped graphene by gas adsorption and effect of external electric field: First-principles study

International Journal of Modern Physics B ◽

10.1142/s0217979219501662 ◽

2019 ◽

Vol 33 (16) ◽

pp. 1950166

Author(s):

Huan Ma ◽

Ling Ma ◽

Liang-Cai Ma

Keyword(s):

Magnetic Properties ◽

Electric Field ◽

External Electric Field ◽

Spin Polarization ◽

First Principles ◽

Density Functional ◽

Gas Adsorption ◽

Doped Graphene ◽

Mn Doped

The effect of gas molecule (H2CO, NO, NO2, O2 and SO2) adsorption on the electronic and magnetic properties of Mn-doped graphene (MnG) is investigated by first-principles calculations in the framework of density functional theory (DFT). Our study reveals that after H2CO, NO, NO2 and SO2 adsorption, MnG transforms from half-metal to semiconductor, and this transformation indicates that MnG’s conductivity is changed significantly. Meanwhile, O2 adsorption has no influence on MnG’s original electronic property. Therefore, the substrate of MnG is highly sensitive to H2CO, NO, NO2 and SO2. The reconfiguration of electron distribution caused by gas adsorption dramatically alters the spin polarization distribution of the combined system, that is, NO2 and H2CO adsorption leads to local spin polarization, whereas O2, NO and SO2 adsorption result in complete spin polarization. In addition, the external electric field (E-field) is varied from −0.50 V/Å to +0.50 V/Å then applied to the adsorption system. A strong interaction is observed between gas and MnG with a positive E-field as reflected in the enhancement of adsorption energy. The interaction is obviously weakened by introducing the E-field in the negative direction. Hence, the adsorption strength and sensitivity of gas on MnG can be effectively tuned by the E-field. The results can serve as useful references for the design of graphene-based gas sensor.