Realization of a hole-doped Mott insulator on a triangular silicon lattice

Abstract

The physics of doped Mott insulators is at the heart of some of the most exotic physical phenomena in materials research including insulator-metal transitions, colossal magneto-resistance, and high-temperature superconductivity in layered perovskite compounds. Advances in this field would greatly benefit from the availability of new material systems with similar richness of physical phenomena, but with fewer chemical and structural complications in comparison to oxides. Using scanning tunneling microscopy and spectroscopy, we show that such a system can be realized on a silicon platform. Adsorption of one-third monolayer of Sn atoms on a Si(111) surface produces a triangular surface lattice with half-filled dangling bond orbitals. Modulation hole-doping of these dangling bonds unveils clear hallmarks of Mott physics, such as spectral weight transfer and the formation of quasi-particle states at the Fermi level, well-defined Fermi contour segments, and a sharp singularity in the density of states. These observations are remarkably similar to those made in complex oxide materials, including high-temperature superconductors, but highly extraordinary within the realm of conventional sp-bonded semiconductor materials. It suggests that exotic quantum matter phases can be realized and engineered on silicon-based materials platforms.

References in corpus (5)

• Scalar spin chirality and quantum Hall effect on a triangular lattice
• Anisotropic Energy Gaps of Iron-based Superconductivity from Intra-band Quasiparticle Interference in LiFeAs
• Triangular Mott-Hubbard Insulator Phases of Sn/Si(111) and Sn/Ge(111) Surfaces
• First direct observation of the Van Hove singularity in the tunneling spectra of cuprates
• Time-Resolved Imaging of Negative Differential Resistance on the Atomic Scale