Origin of the Counterintuitive Dynamic Charge in the Transition-Metal Dichalcogenides

Abstract

We investigate the chemical bonding characteristics of the transition metal dichalcogenides based on their static and dynamical atomic charges within Density Functional Theory. The dynamical charges of the trigonal transition metal dichalcogenides are anomalously large, while in their hexagonal counterparts, their sign is even counterintuitive i.e. the transition metal takes the negative charge. This phenomenon cannot be understood simply in terms of a change in the static atomic charge as it results from a local change of polarization. We present our theoretical understanding of these phenomena based on the perturbative response of the system to a static electric field and by investigating the hybridization of the molecular orbitals near the Fermi level. Furthermore, we establish a link between the sign of the Born effective charge and the $\pi$-backbonding in organic chemistry and propose an experimental procedure to verify the calculated sign of the dynamical charge in the transition metal dichalcogenides.

arXiv comment3 figures, 6 pages

References in corpus (14)

• Phonons and related properties of extended systems from density-functional perturbation theory
• Emerging Device Applications for Semiconducting Two-Dimensional Transition Metal Dichalcogenides
• Ab initio pseudopotentials for electronic structure calculations of poly-atomic systems using density-functional theory
• Second harmonic microscopy of monolayer MoS2
• Libxc: a library of exchange and correlation functionals for density functional theory
• The physics of dynamical atomic charges: the case of ABO3 compounds
• Generation of Projector Augmented-Wave atomic data: a 71 elements validated table in the XML format
• Two-dimensional Fröhlich interaction in transition-metal dichalcogenide monolayers: Theoretical modeling and first-principles calculations
• Born Effective Charges of Barium Titanate: band by band decomposition and sensitivity to structural features
• Interatomic force constants including the DFT-D dispersion contribution
• Fast relaxation of photo-excited carriers in 2D transition metal dichalcogenides
• Electron localization : band-by-band decomposition, and application to oxides
• Band-by-band decomposition of the Born effective charges
• Dynamics of Bulk vs. Nanoscale WS_2: Local Strain and Charging Effects

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