Origin of Distinct Insulating Domains in the Layered Charge Density Wave Material 1T-TaS2

Abstract

Vertical charge order shapes the electronic properties in layered charge density wave (CDW) materials. Various stacking orders inevitably create nanoscale domains with distinct electronic structures inaccessible to bulk probes. Here, the stacking characteristics of bulk 1$T$-TaS$2$ are analyzed using scanning tunneling spectroscopy (STS) and density functional theory (DFT) calculations. It is observed that Mott-insulating domains undergo a transition to band-insulating domains restoring vertical dimerization of the CDWs. Furthermore, STS measurements covering a wide terrace reveal two distinct band insulating domains differentiated by band edge broadening. These DFT calculations reveal that the Mott insulating layers preferably reside on the subsurface, forming broader band edges in the neighboring band insulating layers. Ultimately, buried Mott insulating layers believed to harbor the quantum spin liquid phase are identified. These results resolve persistent issues regarding vertical charge order in 1$T$-TaS$2$, providing a new perspective for investigating emergent quantum phenomena in layered CDW materials.

26 pages and 13 figures

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• Electronic Density of States of a $U\left(1\right)$ Quantum Spin Liquid with Spinon Fermi Surface. I. Orbital Magnetic Field Effects
• Electronic Density of States of a $U\left(1\right)$ Quantum Spin Liquid with Spinon Fermi Surface. II. Zeeman Magnetic Field Effects
• Origin of Distinct Insulating Domains in the Layered Charge Density Wave Material 1T-TaS2
• Behavior under magnetic field of resonance at the edge of the upper Hubbard band in 1T-TaS2

Cited by in corpus (6)

• Charge ordered phases in the hole-doped triangular Mott insulator 4Hb-TaS2
• Origin of Distinct Insulating Domains in the Layered Charge Density Wave Material 1T-TaS2
• Interlayer Hopping between Surface Mott Insulator and Bulk Band Insulator in layered 1T-TaS_{2}
• Topical review: the nature of the ground state and possibility of a quantum spin liquid in 1T metal dichalcogenides
• Interlayer coupling driven phase evolution in hyperbolic $1T$-TaS${}_2$
• Effect of Interlayer Stacking on the Electronic Properties of 1$T$-TaS${}_2$