Charge ordered phases in the hole-doped triangular Mott insulator 4Hb-TaS2

Abstract

4Hb-TaS2 has been proposed to possess unconventional superconductivity with broken time reveral symmetry due to distinctive layered structure, featuring a heterojunction between a 2D triangular Mott insulator and a charge density wave metal. However, since a frustrated spin state in the correlated insulating layer is susceptible to charge ordering with carrier doping, it is required to investigate the charge distribution driven by inter-layer charge transfer to understand its superconductivity. Here, we use scanning tunneling microscopy and spectroscopy (STM/S) to investigate the charge ordered phases of 1T-TaS2 layers within 4Hb-TaS2, explicitly focusing on the non-half-filled regime. Our STS results show an energy gap which exhibits an out-of-phase relation with the charge density. We ascribe the competition between on-site and nonlocal Coulomb repulsion as the driving force for the charge-ordered insulating phase of a doped triangular Mott insulator. In addition, we discuss the role of the insulating layer in the enhanced superconductivity of 4Hb-TaS2.

18 pages, 6 figures

References in corpus (10)

• Superconductivity in single-layer films of FeSe with a transition temperature above 100 K
• An Intrinsic Bond-Centered Electronic Glass with Unidirectional Domains in Underdoped Cuprates
• Charge ordering in the electron-doped superconductor Nd2-xCexCuO4
• Visualization of Topological Boundary Modes Manifesting Topological Nodal-Point Superconductivity
• Triangular Mott-Hubbard Insulator Phases of Sn/Si(111) and Sn/Ge(111) Surfaces
• Realization of a hole-doped Mott insulator on a triangular silicon lattice
• Charge order and superconductivity in a two-dimensional triangular lattice at n=2/3
• Competition between charge and spin order in the $t-U-V$ extended Hubbard model on the triangular lattice
• Honeycomb-Lattice Mott insulator on Tantalum Disulphide
• Origin of Distinct Insulating Domains in the Layered Charge Density Wave Material 1T-TaS2