Strongly Enhanced Charge-Density Waves and Correlated Insulating State in Atomically Thin 1$T$-TaS${}_2$

Abstract

We investigate thickness-dependent charge-density-wave (CDW) transitions in 1$T$-TaS${}_2$ using temperature-dependent Raman spectroscopy and electrical transport. Raman measurements show that the incommensurate, nearly commensurate, and commensurate CDW phases persist down to the monolayer limit. As the thickness is reduced, the transition temperatures increase, accompanied by an orders-of-magnitude rise in sheet resistance and a sharp reduction in the carrier localization length. The first-order hysteretic CCDW-NCCDW transition is uniquely absent in the monolayer. Calculations suggest that the enhanced CDW in thin layers originates from strengthened Coulomb interactions due to reduced out-of-plane screening, particularly in the nonlocal component. These findings highlight the cooperative roles of electron correlation, electron-phonon interaction, and interlayer coupling in shaping the ground state and transition dynamics of atomically thin 1$T$-TaS${}_2$, opening pathways for engineering correlated phases in two-dimensional CDW systems.

References in corpus (27)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Implementation strategies in phonopy and phono3py
• Precision and efficiency in solid-state pseudopotential calculations
• Gate-tunable Phase Transitions in 1T-TaS${}_2$
• Is 1T-TaS${}_2$ a 40 year old quantum spin liquid?
• Orbital textures and charge density waves in transition metal dichalcogenides
• Structure and Control of Charge Density Waves in Two-Dimensional 1T-TaS2
• Visualizing Exotic Orbital Texture in the Single-Layer Mott Insulator 1T-TaSe2
• Efros-Shklovskii variable range hopping in reduced graphene oxide sheets of varying carbon sp2 fraction
• Extended DFT+U+V method with on-site and inter-site electronic interactions
• A new high-temperature quantum spin liquid with polaron spins
• Three Dimensional Metallic and Two Dimensional Insulating Behavior in Tantalum Dichalcogenides
• Mottness versus unit-cell doubling as the driver of the insulating state in 1T-TaS2
• Spinon Fermi surface in a cluster Mott insulator model on a triangular lattice and possible application to 1T-TaS${}_2$
• Zone-center phonons of bulk, few-layer, and monolayer 1T-TaS${}_2$: Detection of the commensurate charge density wave phase through Raman scattering
• Interplay of electron-electron and electron-phonon interactions in the low temperature phase of 1T-TaS2
• Visualization of Chiral Electronic Structure and Anomalous Optical Response in a Material with Chiral Charge Density Waves
• Distinct surface and bulk charge density waves in ultrathin 1T-TaS2
• Effect of Stacking Order on the Electronic State of 1T-TaS${}_2$
• Electrical switching of ferro-rotational order in nano-thick 1T-TaS${}_2$ crystals
• Out-of-plane transport of 1T-TaS2/graphene-based van der Waals heterostructures
• Two-dimensional charge density wave TaX${}_2$ (X=S, Se, Te) from first principles
• Suppression of charge density wave phases in ultrathin 1T-TaS2
• Coupling between Charge, Lattice, Orbital, and Spin in a Charge Density Wave of 1$T$-TaS${}_2$
• Probing charge density wave phases and the Mott transition in $1T$-TaS${}_2$ by inelastic light scattering
• Spectroscopic evidence for possible quantum spin liquid behavior in a two-dimensional Mott insulator