The effect of local magnetic moments on spectral properties and resistivity near the interaction- and doping induced Mott transitions

TL;DR

This study investigates how local magnetic moments influence spectral properties and resistivity near the Mott transition using dynamical mean-field theory, revealing correlations between magnetic screening, quasiparticle formation, and resistivity behavior.

Contribution

It provides a detailed analysis of magnetic moment formation and screening effects on spectral and transport properties near the Mott transition, highlighting the relationship with susceptibilities and resistivity exponents.

Findings

Maximum resistivity at T* coincides with quasiparticle peak formation.

Screening of local magnetic moments occurs at a lower temperature than T*.

Resistivity shows almost linear temperature dependence at low T.

Abstract

We study the effect of the formation and screening of local magnetic moments on the temperature- and interaction dependencies of spectral functions and resistivity in the vicinity of the metal-insulator transition. We use the dynamical mean-field theory for the strongly correlated Hubbard model and associate the peculiarities of the above mentioned properties with those found for the local charge $\chi_c$ and spin $\chi_s$ susceptibilities. We show that at half filling the maximum of resistivity at a certain temperature $T^*$ corresponds to the appearance of central quasiparticle peak of the spectral function and entering the metallic regime with well defined fermionic quasiparticles. At the same time, the temperature of the crossover to the regime with screening of local magnetic moments, determined by the minimum of double occupation, is smaller than the temperature scale $T^*$ and coincides at half filling with the boundary $T_{\beta=1}(U)$ corresponding to the exponent of resistivity $\beta\equiv d\ln \rho/d\ln T=1$. Away from half filling we find weak increase of the temperature of the beginning and completion of the screening (i.e. Kondo temperature) of local magnetic moments, while the unscreened local magnetic moments exist only up to few percents of doping. In the low temperature regime $T<T_{\beta=1}$ simultaneous presence of itinerant and localized degrees of freedom yields almost linear temperature dependence of scattering rate and resistivity.