  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.
