Manipulating Hubbard-type Coulomb blockade effect of metallic wires embedded in an insulator

TL;DR

This study uses advanced microscopy and theoretical modeling to explore and manipulate Coulomb blockade effects in one-dimensional metallic wires within a 2D material, revealing controllable correlated insulating states.

Contribution

It demonstrates the reversible control of Hubbard-type Coulomb blockade states in metallic wires embedded in a 2D material using voltage pulses and provides a theoretical framework for these phenomena.

Findings

Identification of two distinct charge-ordered ground states driven by Coulomb energies.

Reversible switching between ground states via voltage pulses.

Validation of a modified Hubbard model explaining the correlated insulators.

Abstract

Correlated states emerge in low-dimensional systems owing to enhanced Coulomb interactions. Elucidating these states requires atomic scale characterization and delicate control capabilities. In this study, spectroscopic imaging-scanning tunneling microscopy was employed to investigate the correlated states residing in the one-dimensional electrons of the monolayer and bilayer MoSe2 mirror twin boundary (MTB). The Coulomb energies, determined by the wire length, drive the MTB into two types of ground states with distinct respective out-of-phase and in-phase charge orders. The two ground states can be reversibly converted through a metastable zero-energy state with in situ voltage pulses, which tunes the electron filling of the MTB via a polaronic process, as substantiated by first-principles calculations. Our modified Hubbard model reveals the ground states as correlated insulators from an on-site U-originated Coulomb interaction, dubbed Hubbard-type Coulomb blockade effect. Our work sets a foundation for understanding correlated physics in complex systems and for tailoring quantum states for nano-electronics applications.