Patterns and driving forces of dimensionality-dependent charge density waves in 2H-type transition metal dichalcogenides

Abstract

Two-dimensional (2D) materials have become a fertile playground for the exploration and manipulation of novel collective electronic states. Recent experiments have unveiled a variety of robust 2D orders in highly-crystalline materials ranging from magnetism to ferroelectricity and from superconductivity to charge density wave (CDW) instability. The latter, in particular, appears in diverse patterns even within the same family of materials with isoelectronic species. Furthermore, how they evolve with dimensionality has so far remained elusive. Here we propose a general framework that provides a unfied picture of CDW ordering in the 2H polytype of four isoelectronic transition metal dichalcogenides 2H-MX${}_2$ (M=Nb, Ta and X=S, Se). We first show experimentally that whilst NbSe${}_2$ exhibits a strongly enhanced CDW order in the 2D limit, the opposite trend exists for TaSe${}_2$ and TaS${}_2$, with CDW being entirely absent in NbS${}_2$ from its bulk to the monolayer. Such distinct behaviours are then demonstrated to be the result of a subtle, yet profound, competition between three factors: ionic charge transfer, electron-phonon coupling, and the spreading extension of the electronic wave functions. Despite its simplicity, our approach can, in essence, be applied to other quasi-2D materials to account for their CDW response at different thicknesses, thereby shedding new light on this intriguing quantum phenomenon and its underlying mechanisms.

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Cited by in corpus (36)

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• Two-dimensional charge density wave TaX${}_2$ (X=S, Se, Te) from first principles
• Semiconductor-metal phase transition and emergent charge density waves in 1T-ZrX${}_2$ (X = Se, Te) at the two-dimensional limit
• Unconventional charge-density-wave gap in monolayer NbS${}_2$
• Observation of possible excitonic charge density waves and metal-insulator transitions in atomically thin semimetals
• Fermiology and electron-phonon coupling in the 2H and 3R polytypes of NbS${}_2$
• Spin-orbit and exchange proximity couplings in graphene/1T-TaS${}_2$ heterostructure triggered by a charge density wave
• Effects of Nb Doping on the Charge-Density Wave and Electronic Correlations in the Kagome Metal Cs(V${}_{1-x}$Nb${}_x$)${}_3$Sb${}_5$
• Study of charge density waves in suspended 2H-TaS2 and 2H-TaSe2 by nanomechanical resonance
• Ultrafast dynamics in normal and Charge Density Wave phase of 2H-NbSe2
• Electronic Correlations and Evolution of the Charge-Density Wave in the Kagome Metals $A$V${}_3$Sb${}_5$ ($A$ = K, Rb, Cs)
• Probing the interlayer coupling in 2$H$-NbS${}_2$ via soft x-ray angle-resolved photoemission spectroscopy
• Charge density waves and Fermi level pinning in monolayer and bilayer SnSe${}_2$
• Controlling charge density order in 2H-TaSe${}_2$ using a van Hove singularity
• Observation of anomalous amplitude modes in the kagome metal CsV${}_3$Sb${}_5$
• Ab initio electron-lattice downfolding: potential energy landscapes, anharmonicity, and molecular dynamics in charge density wave materials
• Atomic arrangement of van der Waals heterostructures using X-ray scattering and crystal truncation rod analysis
• Anomalous Charge Density Wave State Evolution and Dome-like Superconductivity in CuIr2Te4-xSex Chalcogenides
• Unveiling resilient superconducting fluctuations in atomically thin NbSe${}_2$ through Higgs mode spectroscopy
• Moiré Superstructures in Marginally-Twisted NbSe${}_2$ Bilayers
• Identification of soft modes across the commensurate-to-incommensurate charge density wave transition in 1$T$-TaSe${}_2$
• Charge-density-wave quantum critical point under pressure in 2$H$-TaSe${}_2$
• Investigating the superconducting state of 2$H$-NbS${}_2$ as seen by the vortex lattice
• From orbital to paramagnetic pair breaking in layered superconductor 2H-NbS${}_2$
• Dichotomy of saddle points in energy bands of a monolayer NbSe${}_2$
• Charge Orders in Fully Intercalated Bilayer TaSe${}_2$: Dependence on Interlayer Stacking and Intercalation Sites
• Stacking of charge-density waves in 2H-NbSe${}_2$ bilayers
• Hard ferromagnetism down to the thinnest limit of iron-intercalated tantalum disulfide
• Real-space topology and charge order in the Haldane-Holstein Model
• Evidences for local non-centrosymmetricity and strong phonon anomaly in EuCu2As2: A Raman spectroscopy and lattice dynamics study
• Resonant interlayer coupling in NbSe${}_2$-graphite epitaxial moir{é} superlattices
• Tuning Incommensurate Charge Order in Ba${}_{1-x}$Sr${}_x$Al${}_4$ and Ba${}_{1-y}$Eu${}_y$Al${}_4$
• Dynamical control of Coulomb interactions and Hubbard bands in monolayer 1T-TaS${}_2$
• Raman scattering fingerprints of the charge density wave state in one-dimensional NbTe${}_4$
• Raman spectroscopy of van der Waals topological magnet GdGaI
• Machine learning model for efficient nonthermal tuning of the charge density wave in monolayer NbSe${}_2$