Possible charge instabilities in two-dimensional doped Mott insulators

MAT´ıAS BEJAS, GRECO, AND HIROYUKI YAMASE3

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

American Physical Sociaty

Año: 2012 vol. 86 p. 224509 - 224520

0163-1829

Motivated by the growing evidence of the importance of charge fluctuations in the pseudogap phase in hightemperaturecuprate 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.