Abstract
We study the interactions between the coherent quasiparticles and the incoherent Mott-Hubbard excitations and their effects on the low-energy properties in the Hubbard model. Within the framework of a systematic large- expansion, these effects first occur in the next-to-leading order in . We calculate the scattering phase shift and the free energy, and determine the quasiparticle weight , mass renormalization, and the compressibility. It is found that the compressibility is strongly renormalized and diverges at a critical doping . We discuss the nature of this zero-temperature phase transition and its connection to phase separation and superconductivity.
- Received 16 April 1999
DOI:https://doi.org/10.1103/PhysRevLett.83.2046
©1999 American Physical Society