Microscopic origin of marginal Fermi-liquid in strongly correlated spin systems

M. Crişan, Liviu Tătaru

Józef Spałek

T. V. Ramakrishnan, B. Sriram Shastry

A. P. Protogenov, Dmitry A. Ryndyk

We consider the consequences of separation of spin and charge degrees of freedom in 2+1D strongly correlated spin systems. Self-consistent spin and charge motions induced by doping in sites of ground and dual lattices form such a spectrum of quasiparticles which together with dispersionless character of the collective excitation spectrum and the chemical potential pinning in the band center yield the necessary behavior of charge and spin polarizability to support the theory of marginal liquid formulated by Varma et al. [Phys. Rev. Lett. 63, 1996 (1989)].

Arkady Shekhter, Chandra Mohan Varma

Marginal Fermi liquid was originally introduced as a phenomenological description of the cuprates in a part of the metallic doping range which appears to be governed by fluctuations due to a quantum-critical point. An essential result due to the form of the assumed fluctuation spectra is that the large inelastic quasiparticle relaxation rate near the Fermi surface is proportional to the energy measured from the chemical potential, ${\ensuremath{\tau}}_{i}^{\ensuremath{-}1}\ensuremath{\propto}\ensuremath{\epsilon}$. We present a microscopic long-wavelength derivation of the hydrodynamic properties in such a situation by an extension of the procedure that Eliashberg used for the derivation of the hydrodynamic properties of a Landau-Fermi liquid. In particular, the density-density and the current-current correlations and the relation between the two are derived, and the connection to microscopic calculations of the frequency dependence of the optical conductivity with an additional Fermi-liquid correction factor shown to follow. The method used here may be necessary, quite generally, for the correct hydrodynamic theory for any problem of quantum-critical fluctuations in fermions.

篤史 鶴田