Related papers: Mean-Field Description of Phase String Effect in t…
We consider the implications of spin-phonon coupling within the slave-boson, mean-field treatment of the extended t-J model of a high-temperature superconductor. In bilayer cuprates such as YBaCuO, where the $CuO_2$ plane is buckled, this…
Implication of our recent proposal [J. Phys. Soc. Jpn. 65 (1996) 687] to treat large-amplitude gauge-field fluctuations around the slave-boson mean-field theory for the t-J model has been explored in detail. By attaching gauge flux to…
The main features of a generic boson-fermion scenario for electron pairing in a many-body correlated fermionic system are: i) a cross-over from a poor metal to an insulator and finally a superconductor as the temperature decreases, ii) the…
We attempt to access the regime of strong coupling between charge carriers and transverse dynamics of an isolated conducting ``stripe'', such as those found in cuprate superconductors. A stripe is modeled as a partially doped domain wall in…
We investigate ordered phases (s-wave superconducting (SC), antiferromagnetic (AF) and charge ordered (CO) phases) of the half-filled Holstein-Hubbard model using the dynamical mean-field theory in combination with a continuous time quantum…
We study the slave-boson t-J model of cuprates with high superconducting transition temperatures, and derive its low-energy effective field theory for the charge-spin separated state in a self-consistent manner. The phase degrees of freedom…
We study the stability of the spin gap phase in the U(1) slave-boson theory of the t-J model in connection to the underdoped cuprates. We approach the spin gap phase from the superconducting state and consider the quantum phase transition…
We propose a theory for doped antiferromagnet based on a bosonic resonating-valence-bond (RVB) state with incorporating the phase string effect. Both antiferromagnetic (AF) and superconducting phase transitions occur naturally within such a…
We study the three-dimensional bosonic t-J model, i.e., the t-J model of "bosonic electrons" at finite temperatures. This model describes a system of cold bosonic atoms with two species in an optical lattice. The model is derived from the…
We investigate the superconducting transition in a doped antiferromagnet. Based on the phase string framework of the t-J model, an effective model describing the phase-coherence transition is obtained and is studied through duality…
We introduce a new slave-boson mean-field treatment of the Kondo effect in a quantum dot attached to the leads, when the bias voltage across the leads is finite. The model employs two slave boson and two pseudo-fermion operators to express…
We investigate the phase diagram of phase separation for the hole-doped two dimensional system of antiferromagnetically correlated electrons based on the U(1) slave-boson functional integral approach to the t-J model. We show that the phase…
We reinvestigate a doped antiferromagnetic Mott insulator based on the slave-fermion approach of the t-J model, where antiferromagnetic spin fluctuations and doped holes are described by bosonic spinons and fermionic holons, respectively.…
We present a model which can explain semiquantitatively a number of the unusual properties of \mbox{Yb$_4$As$_3$}. The structural phase transition at $T_{\text{c}}\simeq300\,\mbox{K}$ is described by a band Jahn-Teller effect of correlated…
Two-leg t-J ladders are investigated in the framework of a combination of the phase string formulation and bond-operator representation. We develope a mean-field theory in the strong rung interaction regime, i.e. $J_{\perp}\gg J, t$, which…
The effects of adiabatic phonons on a spin-fermion model for high T_c cuprates are studied using numerical simulations. In the absence of electron-phonon interactions (EPI), stripes in the ground state are observed for certain dopings while…
We analyze the suppression of the phase stiffness in a superconductor by antiferromagnetic order. The analysis is based on a general expression for the phase stiffness in a mean-field state with coexisting spin-singlet superconductivity and…
Using a variational Monte-Carlo approach with a recently proposed stripe wave function, we showed that the strong correlation included in a t-J-type model has essentially all the necessary ingredients to form these stripes with modulations…
We investigate in the framework of linear response theory the complete phonon dispersion, phonon induced electronic charge response, electron-phonon interaction and dielectric and infrared properties of the high-temperature superconductors…
The 2D Hubbard model with large repulsion is a central and yet unsolved problem in condensed matter physics for decades. The challenge appears below half filling, where the system is a doped antiferromagnet. In this regime, the fermion…