Strong particle-hole asymmetry of charge instabilities in doped Mott insulators

Abstract

We study possible charge instabilities in doped Mott insulators by employing the two-dimensional t-J model with a positive value of the next nearest-neighbour hopping integral t on a square lattice, which is applicable to electron-doped cuprates. While the d-wave charge density wave (flux phase) and d-wave Pomeranchuk instability (nematic order) are dominant instabilities for a negative t which corresponds to hole-doped cuprates, we find that those instabilities are strongly suppressed and become relevant only rather close to half-filling. Instead, various types of bond orders with modulation vectors close to (π, π) are dominant in a moderate doping region. Phase separation is also enhanced, but can be suppressed substantially by the nearest-neighbour Coulomb repulsion without affecting the aforementioned charge instabilities.