It is shown, for a small hole doping relative to half filling, that the large-U limit of the Hubbard model (or J=0 limit of the t-J model) exhibits an all-electron Peierls instability towards a state with a charge-density wave. The resulting gap in the spinon spectrum renders the model an insulator.
Barnes, S. E., "All-Electronic Peierls Instability In the Infinite-U Mean-Field Theory For the Hubbard Model" (1990). Physics Articles and Papers. 69.