Metal-nonmetal transition in magnetic systems

Kishore, R.; Joshi, S. K.

doi:10.1088/0022-3719/4/16/013

Cited by 24 publications

(12 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With this definition we introduce the so-called anomalous (off-diagonal) GFs which fix the relevant vacuum and select the proper symmetry broken solutions. In fact, this approximation has been investigated earlier by Kishore and Joshi [50]. They clearly pointed out that they assumed that the system is magnetized in the x direction instead of the conventional z axis.…”

Section: Symmetry Broken Solutionsmentioning

confidence: 96%

Itinerant antiferromagnetism of correlated lattice fermions

Kuzemsky

1999

Physica A: Statistical Mechanics and its Applications

View full text Add to dashboard Cite

The problem of finding of the ferromagnetic and antiferromagnetic "symmetry broken" solutions of the correlated lattice fermion models beyond the mean-field approximation has been investigated. The calculation of the quasiparticle excitation spectra with damping for the single-and multi-orbital Hubbard model has been performed in the framework of the equation-of-motion method for two-time temperature Green's Functions within a nonperturbative approach. A unified scheme for the construction of Generalized Mean Fields (elastic scattering corrections) and self-energy (inelastic scattering) in terms of the Dyson equation has been generalized in order to include the presence of the "source fields". The damping of quasiparticles, which reflects the interaction of the single-particle and collective degrees of freedom has been calculated. The "symmetry broken" dynamical solutions of the Hubbard model, which correspond to various types of itinerant antiferromagnetism has been discussed. This approach complements previous studies and clarifies the nature of the concepts of itinerant antiferromagnetism and "spin-aligning field" of correlated lattice fermions. * Physica A267 (1999) 131-152 †

show abstract

Section: Symmetry Broken Solutionsmentioning

confidence: 96%

Itinerant antiferromagnetism of correlated lattice fermions

Kuzemsky

1999

Physica A: Statistical Mechanics and its Applications

View full text Add to dashboard Cite

show abstract

“…Therefore, the calculation of C(T ) must be performed keeping n constant in the T −µ plane [11]. The energy per atom is E = H N (N being the number of sites of the system) and can be written as [12]:…”

Section: The Modelmentioning

confidence: 99%

“…and G = 4G 1 N q ǫ( k − q)F σ ( q), where ǫ( k − q) = i=0 j 0 t 0 j e i( k− q)• R j and F σ ( q) is given in terms of S j • S i and the Fourier transform of n j0σ and m jσ defined as n 0 jσ = d † 0σ d jσ = 1 N k F ω G (11) kσ e i k• R j and m jσ = d † 0σ n j−σ d jσ = 1 N k F ω G (12) kσ e i k• R j , where F ω Γ(ω) ≡…”

Section: Appendix Amentioning

confidence: 99%

Specific heat of a non-local attractive Hubbard model

Calegari¹,

Lobo²,

Magalhães³

et al. 2013

Physics Letters A

View full text Add to dashboard Cite

The specific heat of an attractive (interaction $G<0$) non-local Hubbard model is investigated. We use a two-pole approximation which leads to a set of correlation functions. In particular, the correlation function $\ <\vec{S}_i\cdot\vec{S}_j\ >$ plays an important role as a source of anomalies in the normal state of the model. Our results show that for a giving range of $G$ and $\delta$ where $\delta=1-n_T$ ($n_T=n_{\uparrow}+n_{\downarrow}$), the specific heat as a function of the temperature presents a two peak structure. Nevertehelesss, the presence of a pseudogap on the anti-nodal points $(0,\pm\pi)$ and $(\pm\pi,0)$ eliminates the two peak structure, the low temperature peak remaining. The effects of the second nearest neighbor hopping on the specific heat are also investigated.Comment: 5 pages, 7 figure

show abstract

“…The Hamiltonian for the model is given by By the method of the double-time temperature dependent Green function (5) we find (in approximations corresponding to the Hartree-Fock one for itinerant electrons (6) and the molecular field one for localized spins) the density of states and selfconsistent equations for the local magnetizations of both subsystems. W e alm study the ground state stability of the magnetic phases.…”

mentioning

confidence: 99%

“…For simplicity, we con- /(a -U)). In this case the system, at low temperatures, is a ferromagnetic = 1 / 2 , x F F 1 (for a square density of states (6), 0…”

mentioning

confidence: 99%