The dynamical spin susceptibility χ( q , ω), of the t-J model in two-dimensional square lattice have been studied based on the mean field approximation to the slave-boson formalism. The static spin susceptibility, χ( q , 0), and Im χ( q , ω) at various energy, ω, have been calculated. We found; 1) χ(0, 0) has only weak temperature dependence 2) T 1 T ∝( T +θ) for $T\gtrsim0.1{J}$ with θ linearly dependent on the doping rate, δ 3) T 1 T has a minimum at T =(0.1∼0.2) J 4) Im χ( q , ω) at q = Q ≡(π, π) has a gap like structure as a function of ω if the temperature is low. All these are consistent with experimental results.The dynamical spin susceptibility χ( q , ω), of the t-J model in two-dimensional square lattice have been studied based on the mean field approximation to the slave-boson formalism. The static spin susceptibility, χ( q , 0), and Im χ( q , ω) at various energy, ω, have been calculated. We found; 1) χ(0, 0) has only weak temperature dependence 2) T 1 T ∝( T +θ) for $T\gtrsim0.1{J}$ with θ linearly dependent on the doping rate, δ 3) T 1 T has a minimum at T =(0.1∼0.2) J 4) Im χ( q , ω) at q = Q ≡(π, π) has a gap like structure as a function of ω if the temperature is low. All these are consistent with experimental results.

Journal of the Physical Society of JapanDec 15, 199182 citations

Magnetic Properties of t∼J Model

Tetsufumi Tanamoto, Kazuhiro Kuboki, Hidetoshi Fukuyama

The dynamical spin susceptibility χ(q, ω), of the t-J model in two-dimensional square lattice have been studied based on the mean field approximation to the slave-boson formalism. The static spin susceptibility, χ(q, 0), and Im χ(q, ω) at various energy, ω, have been calculated. We found; 1) χ(0, 0) has only weak temperature dependence 2) T1T ∝ (T+θ) for T≳0.1J with θ linearly dependent on the doping rate, δ 3) T1T has a minimum at T= (0.1∼0.2)J 4) Im χ(q, ω) at q = Q = (π, π) has a gap like structure as a function of ω if the temperature is low. All these are consistent with experimental results.The dynamical spin susceptibility χ(q, ω), of the t-J model in two-dimensional square lattice have been studied based on the mean field approximation to the slave-boson formalism. The static spin susceptibility, χ(q, 0), and Im χ(q, ω) at various energy, ω, have been calculated. We found; 1) χ(0, 0) has only weak temperature dependence 2) T1T ∝ (T+θ) for T≳0.1J with θ linearly dependent on the doping rate, δ 3) T1T has a minimum at T= (0.1∼0.2)J 4) Im χ(q, ω) at q = Q = (π, π) has a gap like structure as a function of ω if the temperature is low. All these are consistent with experimental results.

Apr 1, 19910 citations

Spin excitations and thermodynamics of the t-J model on the honeycomb lattice

Vladimirov, A., Ihle, D., Plakida, N.

We present a spin-rotation-invariant Green-function theory for the dynamic spin susceptibility in the spin-1/2 antiferromagnetic t-J Heisenberg model on the honeycomb lattice. Employing a generalized mean-field approximation for arbitrary temperatures and hole dopings, the electronic spectrum of excitations, the spin-excitation spectrum and thermodynamic quantities (two-spin correlation functions, staggered magnetization, magnetic susceptibility, correlation length) are calculated by solving a coupled system of self-consistency equations for the correlation functions. The temperature and doping dependence of the magnetic (uniform static) susceptibility is ascribed to antiferromagnetic short-range order. Our results on the doping dependencies of the magnetization and susceptibility are analyzed in comparison with previous results for the t-J model on the square lattice.We present a spin-rotation-invariant Green-function theory for the dynamic spin susceptibility in the spin-1/2 antiferromagnetic t-J Heisenberg model on the honeycomb lattice. Employing a generalized mean-field approximation for arbitrary temperatures and hole dopings, the electronic spectrum of excitations, the spin-excitation spectrum and thermodynamic quantities (two-spin correlation functions, staggered magnetization, magnetic susceptibility, correlation length) are calculated by solving a coupled system of self-consistency equations for the correlation functions. The temperature and doping dependence of the magnetic (uniform static) susceptibility is ascribed to antiferromagnetic short-range order. Our results on the doping dependencies of the magnetization and susceptibility are analyzed in comparison with previous results for the t-J model on the square lattice.

Aug 1, 20184 citations

Spin excitations and thermodynamics of the t-J model on the honeycomb lattice

Artem Vladimirov, Dieter Ihle, Nikolay M. Plakida

We present a spin-rotation-invariant Green-function theory for the dynamic spin susceptibility in the spin-1/2 antiferromagnetic t - J Heisenberg model on the honeycomb lattice. Employing a generalized mean-field approximation for arbitrary temperatures and hole dopings, the electronic spectrum of excitations, the spin-excitation spectrum and thermodynamic quantities (two-spin correlation functions, staggered magnetization, magnetic susceptibility, correlation length) are calculated by solving a coupled system of self-consistency equations for the correlation functions. The temperature and doping dependence of the magnetic (uniform static) susceptibility is ascribed to antiferromagnetic short-range order. Our results on the doping dependencies of the magnetization and susceptibility are analyzed in comparison with previous results for the t - J model on the square lattice.We present a spin-rotation-invariant Green-function theory for the dynamic spin susceptibility in the spin-1/2 antiferromagnetic t - J Heisenberg model on the honeycomb lattice. Employing a generalized mean-field approximation for arbitrary temperatures and hole dopings, the electronic spectrum of excitations, the spin-excitation spectrum and thermodynamic quantities (two-spin correlation functions, staggered magnetization, magnetic susceptibility, correlation length) are calculated by solving a coupled system of self-consistency equations for the correlation functions. The temperature and doping dependence of the magnetic (uniform static) susceptibility is ascribed to antiferromagnetic short-range order. Our results on the doping dependencies of the magnetization and susceptibility are analyzed in comparison with previous results for the t - J model on the square lattice.

arXiv:1803.03140The European Physical Journal BAug 1, 20185 citations

Dynamic spin susceptibility in the t−J model

Artem Vladimirov, Dieter Ihle, Nikolay M. Plakida

A relaxation-function theory for the dynamic spin susceptibility in the $t\text{\ensuremath{-}}J$ model is presented. By a sum-rule-conserving generalized mean-field approximation (GMFA), the two-spin correlation functions of arbitrary range, the staggered magnetization, the uniform static susceptibility, and the antiferromagnetic correlation length are calculated in a wide region of hole doping and temperatures. A good agreement with available exact diagonalization (ED) data is found. The correlation length is in reasonable agreement with neutron-scattering experiments on ${\text{La}}_{2\ensuremath{-}\ensuremath{\delta}}{\text{Sr}}_{\ensuremath{\delta}}{\text{CuO}}_{4}$. Going beyond the GMFA, the self-energy is calculated in the mode-coupling approximation. The spin dynamics at arbitrary frequencies and wave vectors is studied for various temperatures and hole doping. At low doping a spin-wave-type behavior is found as in the Heisenberg model, while at higher doping a strong damping caused by hole hopping occurs, and a relaxation-type spin dynamics is observed in agreement with the ED results. The local spin susceptibility and its $\ensuremath{\omega}/T$ scaling behavior are calculated in a reasonable agreement with experimental and ED data.A relaxation-function theory for the dynamic spin susceptibility in the $t\text{\ensuremath{-}}J$ model is presented. By a sum-rule-conserving generalized mean-field approximation (GMFA), the two-spin correlation functions of arbitrary range, the staggered magnetization, the uniform static susceptibility, and the antiferromagnetic correlation length are calculated in a wide region of hole doping and temperatures. A good agreement with available exact diagonalization (ED) data is found. The correlation length is in reasonable agreement with neutron-scattering experiments on ${\text{La}}_{2\ensuremath{-}\ensuremath{\delta}}{\text{Sr}}_{\ensuremath{\delta}}{\text{CuO}}_{4}$. Going beyond the GMFA, the self-energy is calculated in the mode-coupling approximation. The spin dynamics at arbitrary frequencies and wave vectors is studied for various temperatures and hole doping. At low doping a spin-wave-type behavior is found as in the Heisenberg model, while at higher doping a strong damping caused by hole hopping occurs, and a relaxation-type spin dynamics is observed in agreement with the ED results. The local spin susceptibility and its $\ensuremath{\omega}/T$ scaling behavior are calculated in a reasonable agreement with experimental and ED data.

arXiv:0908.2557Physical Review BSep 21, 200945 citations

Dynamic magnetic susceptibility in the t–J model

Evgeniy V. Kuz’min

The t–J model with a prohibition of “doubles” (doubly occupied sites) in the lower Hubbard band and holes in the upper band is considered in the regime of strong electron correlations. The specific features of the electronic states are described. An expression is obtained for the transverse dynamic susceptibility χ as a function of wave vector q and frequency ω in the random phase approximation (RPA) in the metallic state of the system, and the static susceptibility (ω=0) is analyzed in the limits q=0 and q=Q=(π,π) in a square lattice as a function of the electron density n. The insulating limit (n→1) is described as a spin liquid (SL) state. An expression for the magnetic susceptibility is proposed which unifies the RPA and the SL concept in the presence of site percolation. It is shown that in a certain concentration region the static susceptibility is negative (i.e., a diamagnetic effect), which indicates the possibility of a superconducting state with an exchange mechanism of pairing.The t–J model with a prohibition of “doubles” (doubly occupied sites) in the lower Hubbard band and holes in the upper band is considered in the regime of strong electron correlations. The specific features of the electronic states are described. An expression is obtained for the transverse dynamic susceptibility χ as a function of wave vector q and frequency ω in the random phase approximation (RPA) in the metallic state of the system, and the static susceptibility (ω=0) is analyzed in the limits q=0 and q=Q=(π,π) in a square lattice as a function of the electron density n. The insulating limit (n→1) is described as a spin liquid (SL) state. An expression for the magnetic susceptibility is proposed which unifies the RPA and the SL concept in the presence of site percolation. It is shown that in a certain concentration region the static susceptibility is negative (i.e., a diamagnetic effect), which indicates the possibility of a superconducting state with an exchange mechanism of pairing.

Low Temperature PhysicsFeb 1, 20051 citation

T\gtrsim0.1{J}

with θ linearly dependent on the doping rate, δ 3) T 1 T has a minimum at T =(0.1∼0.2) J 4) Im χ( q , ω) at q = Q ≡(π, π) has a gap like structure as a function of ω if the temperature is low. All these are consistent with experimental results.