Robust ferromagnetism and half-metallicity in hydrogenated monolayer-CdS

Rahman, Altaf Ur; Ullah, Hameed; Jamil, Asif; Iqbal, Zahid; Naveed-Ul-Haq, M.

doi:10.1016/j.physb.2019.06.012

Cited by 14 publications

(7 citation statements)

References 33 publications

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“…The optimized Se–H bond length is 1.54 Å, which larger than the bond length 1.41 Å, in a case H absorbed on the top of S atom in monolayer MoS 2 . This study is consistent with our previous studies of hydrogenated monolayer CdS . The lattice constant optimization indicates that the lattice constant increased to 3.16 Å for hydrogenated Janus CrSSe-ML.…”

Section: Resultssupporting

confidence: 92%

“…3 This study is consistent with our previous studies of hydrogenated monolayer CdS. 48 The lattice constant optimization indicates that the lattice constant increased to 3.16 Å for hydrogenated Janus CrSSe-ML. The enhancement in the lattice constant indicates charge transfer occurred due to the adsorption of a hydrogen atom on the Se-top site in a Janus CrSSe-ML.…”

Section: Resultssupporting

confidence: 91%

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Room Temperature Ferromagnetism in Hydrogenated Janus CrSSe Monolayer Using Quantum Monte Carlo Simulation

Ullah

Shehzadi

Rahman

et al. 2022

Crystal Growth & Design

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Here, using first-principles calculations based on density-functional theory, we propose a novel member of the two-dimensional (2D) transitional metal dichalcogenide family known as a Janus CrSSe monolayer (denoted as CrSSe-ML). The 2D CrSSe-ML has a hexagonal crystal structure. The calculated phonon band structure suggests Janus CrSSe-ML is dynamically stable, and formation energy indicates thermodynamic stability. At the equilibrium lattice constant, it is reported that 2D Janus CrSSe-ML is a non-magnetic semiconductor with a direct bandgap of 0.93 eV (K–K). We found that compressive biaxial strain induces no local magnetic moment, while in contrast the tensile biaxial strain of 12% induces a magnetic moment of 2 μB and half-metallicity which is robust up to 20%. Furthermore, we studied the ferromagnetic (FM) and antiferromagnetic (AFM) coupling between Cr atoms in CrSSe-ML and found that the FM state is favorable over AFM by the amount of energy of 0.007 meV, which is less than 0.03 eV, so no room-temperature ferromagnetism is possible. At the end, we added the H atom at the most preferable Se top-site in a Janus CrSSe-ML and found that hydrogenated Janus CrSSe-ML is magnetic and half-metallic at the equilibrium lattice constant. We further studied FM and AFM calculation by considering fully hydrogenated 4 × 4 × 1 supercell of a Janus CrSSe-ML. We used quantum Monte Carlo simulations (MC) to estimate the Curie temperature (T c) of hydrogenated CrSSe-ML under normal conditions. The calculated value of T c is 553.96 K using the quantum MC simulations. Our calculations predicted that the 2D Janus CrSSe-ML material is a promising candidate for spintronic device applications above room temperature.

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Section: Resultssupporting

confidence: 92%

Section: Resultssupporting

confidence: 91%

Room Temperature Ferromagnetism in Hydrogenated Janus CrSSe Monolayer Using Quantum Monte Carlo Simulation

Ullah

Shehzadi

Rahman

et al. 2022

Crystal Growth & Design

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“…Before that, it had been predicted that substitutional doping of transition metals (TMs) (Mn, Ni, Cr, Fe, and Si, etc) in semiconductors could induce room temperature FM [29]. More recently, this possibility has been investigated in both bulk and monolayer MMCs [30,31].…”

Section: Introductionmentioning

confidence: 99%

First-principles computational exploration of ferromagnetism in monolayer GaS via substitutional doping

Khan¹,

Rahman²,

Zhang³

et al. 2021

J. Phys.: Condens. Matter

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Using first-principles calculations, functionalization of the monolayer-GaS crystal structure through N or Cr-doping at all possible lattice sites has been investigated. Our results show that pristine monolayer-GaS is an indirect-bandgap, non-magnetic semiconductor. The bandgap can be tuned and a magnetic moment (MM) can be induced by the introduction of N or Cr atomic anion/cation doping in monolayer GaS. For instance, the intrinsic character of monolayer GaS can be changed by substitution of N for the S-site to p-type, while substitution of Cr at the S-site or Ga-site induces half-metallicity at sufficiently high concentrations. The defect states are located in the electronic bandgap region of the GaS monolayer. These findings help to extend the application of monolayer-GaS structures in nano-electronics and spintronics. Since the S-sites at the surface are more easily accessible to doping in experiment, we chose the S-site for further investigations. Finally, we perform calculations with ferromagnetic (FM) and antiferromagnetic (AFM) alignment of the MMs at the dopants. For pairs of impurities of the same species at low concentrations we find Cr atoms to prefer the FM state, while N atoms prefer the AFM state, both for impurities on opposite surfaces of the GaS monolayer and for impurities sharing a common Ga neighbor sitting at the same surface. Extending our study to higher concentrations of Cr atoms, we find that clusters of four Cr atoms prefer AFM coupling, whereas the FM coupling is retained for Cr atoms at larger distance arranged on a honeycomb lattice. For the latter arrangement, we estimate the FM Curie temperature T C to be 241 K. We conclude that the Cr-doped monolayer-GaS crystal structure offers enhanced electronic and magnetic properties and is an appealing candidate for spintronic devices operating close to room temperature.

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“…The optimized lattice constant for Yb +2 doped CsCaCl 3 at concentration levels of 5% and 10% is 5.45 Å and 5.46 Å, respectively, which is slightly elongated from the equilibrium lattice constant of pristine CsCaCl 3 . The elongation from the equilibrium lattice constant increases the thermal stability of the material [16,31]. So at higher dopant concentrations, the substitution of Ca atom with Yb +2 would induce slight local structure distortions.…”

Section: Effect Of Yb +2 Cation Doping On the Crystal Structurementioning

confidence: 99%

The effect of substitutional doping of Yb²⁺ on structural, electronic, and optical properties of CsCaX ₃ (X: Cl, Br, I) phosphors: a first-principles study

Khan

Rahman

Zhang

et al. 2021

J. Phys.: Condens. Matter

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Using first-principles calculations, the effects of Yb2+ substitutional doping on structural, electronic, and optical properties of a series of perovskite compounds CsCaX 3 (X: Cl, Br, I), have been investigated. We employed generalized gradient approximation (GGA) and HSE hybrid functional to study the electronic and optical properties. A series of pristine CsCaX 3 (X: Cl, Br, I) is characterized as a non-magnetic insulator with indirect bandgap perovskite materials. These phosphor materials are suitable candidates for doping with lanthanide series elements to tune their electronic bandgaps according to our requirements because of their wide bandgaps. The calculated electronic bandgaps of CsCaX 3 (X: Cl, Br, I) are 3.7 eV (GGA) and 4.5 eV (HSE) for CsCaI3, 4.5 eV (GGA) and 5.3 eV (HSE) for CsCaBr3, and 5.4 eV (GGA) and 6.4 eV (HSE) for CsCaCl3. According to formation energies, the Yb2+ doped at the Ca-site is thermodynamically more stable as compared to all possible atomic sites. The electronic band structures show that the Yb2+ doping induces defective states within the bandgaps of pristine CsCaX 3 (X: Cl, Br, I). As a result, the Yb2+ doped CsCaX 3 (X: Cl, Br, I) become the direct bandgap semiconductors. The defective states above the valence band maximum are produced due to the f-orbital of the Yb atom. The impurity states near the conduction band minimum are induced due to the major contribution of d-orbital of the Yb atom and the minor contribution of s-orbital of the Cs atom. The real and imaginary parts of the dielectric function, optical reflectivity, electron energy loss spectrum, extinction coefficient, and refractive index of pristine and Yb2+ doped CsCaX 3 (X: Cl, Br, I) were studied. The optical dispersion results of dielectric susceptibility closely match their relevant electronic structure and align with previously reported theoretical and experimental data. We conclude that the Yb2+ doped CsCaX 3 (X: Cl, Br, I) are appealing candidates for optoelectronic devices.

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Robust ferromagnetism and half-metallicity in hydrogenated monolayer-CdS

Cited by 14 publications

References 33 publications

Room Temperature Ferromagnetism in Hydrogenated Janus CrSSe Monolayer Using Quantum Monte Carlo Simulation

Room Temperature Ferromagnetism in Hydrogenated Janus CrSSe Monolayer Using Quantum Monte Carlo Simulation

First-principles computational exploration of ferromagnetism in monolayer GaS via substitutional doping

The effect of substitutional doping of Yb²⁺ on structural, electronic, and optical properties of CsCaX ₃ (X: Cl, Br, I) phosphors: a first-principles study

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Robust ferromagnetism and half-metallicity in hydrogenated monolayer-CdS

Cited by 14 publications

References 33 publications

Room Temperature Ferromagnetism in Hydrogenated Janus CrSSe Monolayer Using Quantum Monte Carlo Simulation

Room Temperature Ferromagnetism in Hydrogenated Janus CrSSe Monolayer Using Quantum Monte Carlo Simulation

First-principles computational exploration of ferromagnetism in monolayer GaS via substitutional doping

The effect of substitutional doping of Yb2+ on structural, electronic, and optical properties of CsCaX 3 (X: Cl, Br, I) phosphors: a first-principles study

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The effect of substitutional doping of Yb²⁺ on structural, electronic, and optical properties of CsCaX ₃ (X: Cl, Br, I) phosphors: a first-principles study