Phase Diagram of Electron Doped Dichalcogenides

Abstract

Using first principle calculations, we examine the sequence of phases in electron doped dichalcogenides, such as recently realized in field-gated MoS${}_2$. Upon increasing the electron doping level, we observe a succession of semiconducting, metallic, superconducting and charge density wave regimes, i.e. in different order compared to the phase diagram of (semi-)metallic dichalcogenides such as TiSe${}_2$. Both instabilities trace back to a softening of phonons which couple the electron populated conduction band minima. The superconducting dome, calculated using Eliashberg theory, is found to fit the experimentally observed phase diagram, obtained from resistivity measurements. The charge density wave phase at higher electron doping concentrations as predicted from instabilities in the phonon modes is further corroborated by detecting the accompanying lattice deformation in density functional based supercell relaxations. Upon charge density wave formation, doped MoS${}_2$ remains metallic but undergoes a Lifschitz transition, where the number of Fermi pockets is reduced.

5 pages, 4 figures

References in corpus (3)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Two Dimensional Atomic Crystals
• Effect of modulations of doping and strain on the electron transport in monolayer MoS_2

Cited by in corpus (15)

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• Evidence of ideal excitonic insulator in bulk MoS2 under pressure
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• Metal-Insulator Transition and Emergent Gapped Phase in the Surface-Doped 2D Semiconductor 2H-MoTe${}_2$
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• Multiple odd-parity superconducting phases in bilayer transition metal dichalcogenides
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• Competition between phonon mediated superconductivity and carriers localization in field-effect doped molybdenum dichalcogenides
• Strong band-filling-dependence of the scattering lifetime in gated MoS2 nanolayers induced by the opening of intervalley scattering channels
• Anomalous metallic phase in molybdenum disulphide induced via gate-driven organic ion intercalation
• Optically and electrically controllable adatom spin-orbital dynamics in transition metal dichalcogenides