title: Local density of states of one-dimensional Mott insulators and charge-density wave states with a boundary.
abstract: We determine the local density of states of one-dimensional incommensurate charge-density wave states in the presence of a strong impurity potential, which is modeled by a boundary. We find that the charge-density wave gets pinned at the impurity, which results in a singularity in the Fourier transform of the local density of states at momentum 2k_{F}. At energies above the spin gap we observe dispersing features associated with the spin and charge degrees of freedom, respectively. In the presence of an impurity magnetic field we observe the formation of a bound state localized at the impurity. All of our results carry over to the case of 1D Mott insulators by exchanging the roles of spin and charge degrees of freedom. We discuss the implications of our result for scanning tunneling microscopy experiments on spin-gap systems such as two-leg ladder cuprates.
authors.affiliation: The Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, OX1 3NP Oxford, United Kingdom.
authors.forename: Dirk
authors.initials: D
authors.lastname: Schuricht
authors.forename: Fabian H L
authors.initials: FH
authors.lastname: Essler
authors.forename: Akbar
authors.initials: A
authors.lastname: Jaefari
authors.forename: Eduardo
authors.initials: E
authors.lastname: Fradkin