  We determine the local density of states (LDOS) for spin-gapped
one-dimensional charge density wave (CDW) states and Mott insulators in the
presence of a hard-wall boundary. We calculate the boundary contribution to the
single-particle Green function in the low-energy limit using field theory
techniques and analyze it in terms of its Fourier transform in both time and
space. The boundary LDOS in the CDW case exhibits a singularity at momentum
2kF, which is indicative of the pinning of the CDW order at the impurity. We
further observe several dispersing features at frequencies above the spin gap,
which provide a characteristic signature of spin-charge separation. This
demonstrates that the boundary LDOS can be used to infer properties of the
underlying bulk system. In presence of a boundary magnetic field mid-gap states
localized at the boundary emerge. We investigate the signature of such bound
states in the LDOS. We discuss implications of our results on STM experiments
on quasi-1D systems such as two-leg ladder materials like Sr14Cu24O41. By
exchanging the roles of charge and spin sectors, all our results directly carry
over to the case of one-dimensional Mott insulators.
