Interlayer charge transfer induced by electronic instabilities in the natural van der Waals hetrostructure 4H${}_b$-TaS${}_2$

Abstract

The natural van der Waals heterostructure 4H${}_b$-TaS${}_2$ composed of alternating 1T- and 1H-TaS${}_2$ layers serves as a platform for investigating the electronic correlations and layer-dependent properties of novel quantum materials. The temperature evolution of the conductivity spectra $\sigma (\omega )$ obtained through infrared spectroscopy elucidates the influence of band modifications associated with the charge-density-wave (CDW) superlattice on the 1T layer, resulting in a room-temperature energy gap, ${\Delta }_{\mathrm{CDW}}\approx$ 0.35 eV. However, there is no gap associated to the 1H layer. Supported by density functional theory calculations, we attribute the behavior of interband transitions to the convergence of the layers, which amplifies the charge transfer from the 1T to the 1H layers, progressing as the temperature decreases. This phenomenon leads to an enhanced low-energy spectral weight and carrier density. The presence of an energy gap and the temperature-tunable charge transfer within the bulk of 4H${}_b$-TaS${}_2$ driven by layer-dependent CDW states contribute to a more comprehensive understanding of other complex compounds of transition-metal dichalcogenides.

11 pages including SM

References in corpus (24)

• 2D materials and van der Waals heterostructures
• The remarkable underlying ground states of cuprate superconductors
• Band insulator to Mott insulator transition in 1T-TaS${}_2$
• Structural phase transition in IrTe${}_2$: A combined study of optical spectroscopy and band structure calculations
• Visualization of Topological Boundary Modes Manifesting Topological Nodal-Point Superconductivity
• Optical detection of charge-density-wave instability in the non-magnetic kagome metal KV${}_3$Sb${}_5$
• Low-energy optical properties of the non-magnetic kagome metal CsV${}_3$Sb${}_5$
• Coexistence and competition of multiple charge-density-wave orders in rare-earth tri-telluride RTe3
• Softening of a flat phonon mode in the kagome ScV${}_6$Sn${}_6$
• Polaronic conductivity in the photoinduced phase of 1T-TaS2
• Optical spectroscopy and band structure calculations of structural phase transition in the Vanadium-based kagome metal ScV${}_6$Sn${}_6$
• Phonon anomaly at the charge ordering transition in 1T-TaS2
• Roles of the Narrow Electronic Band near the Fermi Level in 1T-TaS${}_2$-Related Layered Materials
• Optical study of the charge-density-wave mechanism in 2$H$-TaS${}_2$ and Na${}_x$TaS${}_2$
• Chiral charge order in the superconductor 2H-TaS2
• Optical study of RbV${}_3$Sb${}_5$: Multiple density-wave gaps and phonon anomalies
• Alternating superconducting and charge density wave monolayers within bulk 6R-TaS2
• Heterogeneous Ta-dichalcogenide bilayer: heavy fermions or doped Mott physics?
• Chiral charge density waves induced by Ti-doping in 1T-TaS2
• Intriguing Low-Temperature Phase in the Antiferromagnetic Kagome Metal FeGe
• Pressure induced nonmonotonic evolution of superconductivity in 6R-TaS2 with a natural bulk van der Waals heterostructure
• Optical spectroscopy and ultrafast pump-probe study of structural phase transition in 1T'-TaTe2
• Understanding the flat band in 1T-TaS2 using a rotated basis
• Interlayer Hopping between Surface Mott Insulator and Bulk Band Insulator in layered 1T-TaS_{2}