Non-Fermi Behavior of the Strongly Correlated Electron Systems

TL;DR

This paper investigates non-Fermi liquid behavior in strongly correlated electron systems through theoretical calculations of specific heat, self-energy, and fluctuations, revealing novel properties and transitions in two-dimensional models.

Contribution

It provides new theoretical insights into non-Fermi behavior in 2D electron systems, including calculations of specific heat, self-energy, and the effects of fluctuations, advancing understanding of correlated materials.

Findings

Non-Fermi behavior in 2D fermionic systems with hyperbolic dispersion.

Calculated specific heat and self-energy showing marginal and non-Fermi characteristics.

Studied the evolution from BCS to BEC in non-Fermi systems using field theory.

Abstract

(1) The temperature dependence of the specific heat for a marginal Fermi liquid has been calculated. (2) We calculated the self-energy at T=0 for a two dimensional fermionic system with hyperbolic dispersion. The existence of the saddle points in the energy gives rise to a marginal behavior. (3) We showed that the two-dimensional fermionic system with the energy $\epsilon _{\mathbf{k}}=k_xk_y$ has a non-Fermi behavior. (4) The electronic self-energy due to the electron-spin interaction is calculated for a two dimensional system. (5) We study the influence of the amplitude fluctuations of a non-Fermi superconductor on the energy spectrum of the two-dimensional Anderson non-Fermi system. (6) Using the field-theoretical methods we studied the evolution from BCS theory to Bose-Einstein condensation (BEC) for a non-Fermi system. (7) Using the renormalization group approach proposed by Millis we calculated the specific heat coefficient $\gamma (T)$ for the magnetic fluctuations with susceptibility $\chi^{-1}\sim \delta ^{\alpha}+| \omega | ^{\alpha}+f(q)$ near a Lifshitz point.