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 simulation of the structure and transport properties of zirconium and ferromagnetic cobalt contacts on the two-dimensional semiconductor 
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Kahnouji, Hamideh; Kratzer, Peter; Hashemifar, S. Javad

doi:10.1103/physrevb.99.035418

Cited by 7 publications

(3 citation statements)

References 31 publications

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“…For example, a color scale is used to indicate the contribution of a certain orbital to a band, or symbols with sizes proportional to the admixture of a certain orbital are plotted on top of the line plot of the band structure. This is illustrated in Figure 10 for the example of a zirconium contact on the two-dimensional semiconductor WS 2 (Kahnouji et al, 2019). The band structure and the PDOS have been calculated with the FHI-aims code (Blum et al, 2009).…”

Section: Analysis Toolsmentioning

confidence: 99%

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The Basics of Electronic Structure Theory for Periodic Systems

Kratzer

Neugebauer

2019

Front. Chem.

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When density functional theory is used to describe the electronic structure of periodic systems, the application of Bloch's theorem to the Kohn-Sham wavefunctions greatly facilitates the calculations. In this paper of the series, the concepts needed to model infinite systems are introduced. These comprise the unit cell in real space, as well as its counterpart in reciprocal space, the Brillouin zone. Grids for sampling the Brillouin zone and finite k-point sets are discussed. For metallic systems, these tools need to be complemented by methods to determine the Fermi energy and the Fermi surface. Various schemes for broadening the distribution function around the Fermi energy are presented and the approximations involved are discussed. In order to obtain an interpretation of electronic structure calculations in terms of physics, the concepts of bandstructures and atom-projected and/or orbital-projected density of states are useful. Aspects of convergence with the number of basis functions and the number of k-points need to be addressed specifically for each physical property. The importance of this issue will be exemplified for force constant calculations and simulations of finite-temperature properties of materials. The methods developed for periodic systems carry over, with some reservations, to less symmetric situations by working with a supercell. The chapter closes with an outlook to the use of supercell calculations for surfaces and interfaces of crystals.

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Section: Analysis Toolsmentioning

confidence: 99%

“…Although the contact as a whole is metallic, one can still see remainders of the valence band and conductance band of the semiconductor WS 2 in the bands marked by the red symbols. Figure adopted from Kahnouji et al (2019).…”

Section: Analysis Toolsmentioning

confidence: 99%

The Basics of Electronic Structure Theory for Periodic Systems

Kratzer

Neugebauer

2019

Front. Chem.

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“…To assist in the analysis and assignment of the PL transitions observed at low temperatures, we performed DFT calculations to identify the role of alloying on the electronic band structure and in particular, on the energy levels of the predominant defect center, namely sulfur vacancy, V S . Most theoretical work regarding the spin-orbit coupling effect in TMDCs considered pristine MoS 2 and WS 2 , where the spin-orbit splitting between the spinup and spin-down states in WS 2 and MoS 2 monolayers are calculated to be 0.4 eV [52,53] and 0.15 eV. [54][55][56] This splitting effect is largely responsible for the production of the A and B excitons in these pristine samples [57,58] (observed in PL spectra measurements due to spin-allowed bright excitonic transitions).…”

Section: Dft Calculationsmentioning

confidence: 99%

Sulfur Vacancy Related Optical Transitions in Graded Alloys of Mo_xW_1‐xS₂ Monolayers

Ghafariasl,

Zhang,

Ward

et al. 2024

Advanced Optical Materials

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Engineering electronic bandgaps is crucial for applications in information technology, sensing, and renewable energy. Transition metal dichalcogenides (TMDCs) offer a versatile platform for bandgap modulation through alloying, doping, and heterostructure formation. Here, the synthesis of a 2D MoxW1‐xS2 graded alloy is reported, featuring a Mo‐rich center that transitions to W‐rich edges, achieving a tunable bandgap of 1.85 to 1.95 eV when moving from the center to the edge of the flake. Aberration‐corrected high‐angle annular dark‐field scanning transmission electron microscopy showed the presence of sulfur monovacancy, VS, whose concentration varied across the graded MoxW1‐xS2 layer as a function of Mo content with the highest value in the Mo‐rich center region. Optical spectroscopy measurements supported by ab initio calculations reveal a doublet electronic state of VS, which is split due to the spin‐orbit interaction, with energy levels close to the conduction band or deep in the bandgap depending on whether the vacancy is surrounded by W atoms or Mo atoms. This unique electronic configuration of VS in the alloy gave rise to four spin‐allowed optical transitions between the VS levels and the valence bands. The study demonstrates the potential of defect and optical engineering in 2D monolayers for advanced device applications.

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Deciphering Sodium‐Ion Storage: 2D‐Sulfide versus Oxide Through Experimental and Computational Analyses

Sengupta,

Pramanik,

de Oliveira

et al. 2024

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Transition metal derivatives exhibit high theoretical capacity, making them promising anode materials for sodium‐ion batteries. Sulfides, known for their superior electrical conductivity compared to oxides, enhance charge transfer, leading to improved electrochemical performance. Here, a hierarchical WS2 micro‐flower is synthesized by thermal sulfurization of WO3. Comprising interconnected thin nanosheets, this structure offers increased surface area, facilitating extensive internal surfaces for electrochemical redox reactions. The WS2 micro‐flower demonstrates a specific capacity of ≈334 mAh g−1 at 15 mA g−1, nearly three times higher than its oxide counterpart. Further, it shows very stable performance as a high‐temperature (65 °C) anode with ≈180 mAh g−1 reversible capacity at 100 mA g−1 current rate. Post‐cycling analysis confirms unchanged morphology, highlighting the structural stability and robustness of WS2. DFT calculations show that the electronic bandgap in both WS2 and WO3 increases when going from the bulk to monolayers. Na adsorption calculations show that Na atoms bind strongly in WO3 with a higher energy diffusion barrier when compared to WS2, corroborating the experimental findings. This study presents a significant insight into electrode material selection for sodium‐ion storage applications.

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Abinitio simulation of the structure and transport properties of zirconium and ferromagnetic cobalt contacts on the two-dimensional semiconductor WS2

Cited by 7 publications

References 31 publications

The Basics of Electronic Structure Theory for Periodic Systems

The Basics of Electronic Structure Theory for Periodic Systems

Sulfur Vacancy Related Optical Transitions in Graded Alloys of Mo_xW_1‐xS₂ Monolayers

Deciphering Sodium‐Ion Storage: 2D‐Sulfide versus Oxide Through Experimental and Computational Analyses

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Abinitio simulation of the structure and transport properties of zirconium and ferromagnetic cobalt contacts on the two-dimensional semiconductor WS2

Cited by 7 publications

References 31 publications

The Basics of Electronic Structure Theory for Periodic Systems

The Basics of Electronic Structure Theory for Periodic Systems

Sulfur Vacancy Related Optical Transitions in Graded Alloys of MoxW1‐xS2 Monolayers

Deciphering Sodium‐Ion Storage: 2D‐Sulfide versus Oxide Through Experimental and Computational Analyses

Contact Info

Product

Resources

About

Sulfur Vacancy Related Optical Transitions in Graded Alloys of Mo_xW_1‐xS₂ Monolayers