Computational methods and destruction of the Fermi liquid in systems of correlated lattice electrons

篤史 鶴田

Claudio Castellani, C. Di Castro

Connor Lenihan

T. McMullen

Several experimental techniques, such as photoemission, Compton scattering, and positron annihilation, use the excitation or destruction of an electron to measure the momentum distribution of the electrons. The structure in these momentum distributions that results from the Fermi surface of a Fermi liquid is well known, but structure can also arise from the electron correlations in a strongly correlated system. The momentum distribution of a highly correlated two-dimensional electron system in which the spin and charge degrees of freedom are decoupled is examined using, as a model system, a noninteracting spinon-holon description of the excitations of the two-dimensional Hubbard model.

Fabian Eickhoff, Frithjof B. Anders

In this paper we consider a multi-band extension to the periodic Anderson model. We use a single site DMFT(NRG) in order to study the impact of the conduction band mediated effective hopping of the correlated electrons between the correlated orbitals onto the heavy Fermi-liquid formation. Whereas the hybridization of a single impurity model with two distinct conduction bands always adds up constructively, T_{K}\propto \exp(-\mathrm{const}\, U/(\Gamma_1+\Gamma_2)) T K ∝ exp ( − c o n s t U / ( Γ 1 + Γ 2 ) ) , we show that this does not have to be the case in lattice models, where, in remarkable contrast, also an low-energy Fermi-liquid scale T_0\propto \exp(-\mathrm{const}\, U/(\Gamma_1-\Gamma_2)) T 0 ∝ exp ( − c o n s t U / ( Γ 1 − Γ 2 ) ) can emerge due to quantum interference effects in multi-band models, where U U denotes the local Coulomb matrix element of the correlated orbitals and \Gamma_i Γ i the local hybridization strength of band i i . At high symmetry points, heavy Fermi-liquid formation is suppressed which is associated with a breakdown of the Kondo effect. This results in an asymptotically scale-invariant (i.e., power-law) spectrum of the correlated orbitals \propto|\omega|^{1/3} ∝ | ω | 1 / 3 , indicating non-Fermi liquid properties of the quantum critical point, and a small Fermi surface including only the light quasi-particles. This orbital selective Mott phase demonstrates the possibility of metallic local criticality within the general framework of ordinary single site DMFT.

Yu-Liang Liu

In framework of eigen-functional bosonization method, we introduce an imaginary phase field to uniquely represent electron correlation, and demonstrate that the Landau Fermi liquid theory and the Tomonaga-Luttinger liquid theory can be unified. It is very clear in this framework that the Tomonaga-Luttinger liquid behavior of one-dimensional interacting electron gases originates from their Fermi structure, and the non-Landau-Fermi liquid behavior of 2D interacting electron gases is induced by the long-range electron interaction, while 3D interacting electron gases generally show the Landau Fermi liquid behavior.