Possible charge instabilities in two-dimensional doped Mott insulators

BEJAS, MATÍAS; GRECO, ANDRÉS; YAMASE, HIROYUKI

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2012 vol. 86 p. 1 - 12

1098-0121

Motivated by the growing evidence of the importance of charge fluctuations in the pseudogap phase in high-temperature cuprate superconductors, we apply a large-N expansion formulated in a path integral representationof the two-dimensional t-J model on a square lattice. We study all possible charge instabilities of the paramagneticstate in leading order of the 1/N expansion. While the d-wave charge density wave (flux phase) becomes theleading instability for various choices of model parameters, we find that a d-wave Pomeranchuk (electronicnematic phase) instability occurs as a next leading one. In particular, the nematic state has a strong tendency tobecome inhomogeneous. In the presence of a large second nearest-neighbor hopping integral, the flux phase issuppressed and the electronic nematic instability becomes leading in a high doping region. Besides these twomajor instabilities, bond-order phases occur as weaker instabilities close to half-filling. Phase separation is alsodetected in a finite temperature region near half-filling.