A theory of resistivity in Kondo lattice materials: memory function approach

Abstract

We have theoretically analysed DC resistivity (ρ) in the Kondo-lattice materials using the powerful memory function formalism. The complete temperature evolution of ρ is investigated using the Wöl e-Götze expansion of the memory function. The resistivity in this model originates from spin-ip magnetic scattering of conduction s-electron off the quasi-localized d or f electron spins. We nd the famous resistivity upturn in lower temperature regime (k B T ≪ µ d ), where µ d is the effective chemical potential of d-electrons. In the high temperature regime (µ d ≪ k B T) we discover that resistivity scales as cube root of T (ρ ∝ T 3 2 ). Our results are in reasonable agreement with the experimental results reported in the literature.

Non-Drude behaviour of optical conductivity in Kondo-lattice systems

“…here J is coupling constant between s-electron and d electrons [5]. c † and c are the creation and annihilation operators for s-electrons.…”

“…Under the assumption of weak coupling (electron K.E. J) between the s and d electrons the Wölfle-Götze equation of motion method defines the memeory function as [5,6,7,8]…”

“…kσ is the current density operator and V is volume of the sample. I define the current-current correlator as φ(z) = J1 ; J1 and compute the correlator in terms of fermi functions of electrons(for more details refer to [5]), we get…”

“…From the above expression the imginary part of the memory function can be written as (for more details refer to ref. [5])…”

Electrical resistivity in 2d Kondo lattice systems

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I extend the calculations represented in [4] regarding the resistivity in Kondo lattice materials from 3d syatem to 2d systems. In the present work I consider a 2d system, and memory function is computed.

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