Momentum space anisotropy in doped Mott insulators

In this paper we explore the incommensurate spatial modulation of spin-spin correlations as the intrinsic property of the doped Mott insulator, described by the $t-J$ model. We show that such an incommensurability is a direct manifestation of the phase string effect introduced by doped holes in both one- and two-dimensional cases. The magnetic incommensurate peaks of dynamic spin susceptibility in momentum space are in agreement with the neutron-scattering measurement of cupr...

Trial wavefunctions, constructed explicitly from the unique 2-dimensional Mott insulating state with antiferromagnetic order, are proposed to describe the low-energy states of a Mott insulator slightly doped with holes or electrons. With the state behaving like charged quasi-particles with well-defined momenta, a rigid band is observed. These states have much less pairing correlations than previously studied ones. Small Fermi patches obtained are consistent with recent experi...

In the recent studies of the unconventional physics in cuprate superconductors, one of the central issues is the interplay between charge order and superconductivity. Here the mechanism of the charge-order formation in the electron-doped cuprate superconductors is investigated based on the t-J model. The experimentally observed momentum dependence of the electron quasiparticle scattering rate is qualitatively reproduced, where the scattering rate is highly anisotropic in mome...

In strongly correlated electron systems, the emergence of states in the Mott gap in the single-particle spectrum following the doping of the Mott insulator is a remarkable feature that cannot be explained in a conventional rigid-band picture. Here, based on an analysis of the quantum numbers and the overlaps of relevant states, as well as through a demonstration using the ladder and bilayer t-J models, it is shown that in a continuous Mott transition due to hole doping, the m...

We demonstrate that a Mott insulator lightly doped with holes is still an insulator at low temperature even without disorder. Hole localization obtains because the chemical potential lies in a pseudogap which has a vanishing density of states at zero temperature. The energy scale for the pseudogap is set by the nearest-neighbour singlet-triplet splitting. As this energy scale vanishes if transitions, virtual or otherwise, to the upper Hubbard band are not permitted, the funda...

With the hierarchical Green's function approach, we study a doped Mott insulator described with the Hubbard model by analytically solving the equations of motion of an one-particle Green's function and related multiple-point correlation functions, and find that the separation of the spin and charge degrees of freedom of the electrons is an intrinsic character of the doped Mott insulator. For enough of large on-site repulsive Coulomb interaction, we show that the spectral weig...

With the aid of both a semi-analytical and a numerically exact method we investigate the charge dynamics in the vicinity of half-filling in the one- and two-dimensional $t$-$J$ model derived from a Fermi-Hubbard model in the limit of large interaction $U$ and hence small exchange coupling $J$. The spin degrees of freedom are taken to be disordered. So we consider the limit $0 < J \ll T \ll W$ where $W$ is the band width. We focus on evaluating the spectral density of a single...

We show that lightly doped holes will be self-trapped in an antiferromagnetic spin background at low-temperatures, resulting in a spontaneous translational symmetry breaking. The underlying Mott physics is responsible for such novel self-localization of charge carriers. Interesting transport and dielectric properties are found as the consequences, including large doping-dependent thermopower and dielectric constant, low-temperature variable-range-hopping resistivity, as well ...

We demonstrate that the sign structure of the t-J model on a hypercubic lattice is entirely different from that of a Fermi gas, by inspecting the high temperature expansion of the partition function up to all orders, as well as the multi-hole propagator of the half-filled state and the perturbative expansion of the ground state energy. We show that while the fermion signs can be completely gauged away by a Marshall sign transformation at half-filling, the bulk of the signs ca...

We introduce the concept that there are two generic classes of Mott insulators in nature. They are distinguished by their responses to weak doping. Doped charges form cluster (i.e. distribute inhomogeneously) in type I Mott insulators while distribute homogeneously in type II Mott insulators. We present our opinion on the role inhomogeneity plays in the cuprates.