arXiv subjects

Arianna Poli

Publications and source records attributed to Arianna Poli.

3 recordsLinked to original sources

arXiv2025

Fragility of local moments against hybridization with flat bands

The Kondo screening of a localized magnetic moment crucially depends on the spectral properties of the electronic bath to which it is coupled. Unlike textbook examples, realistic systems as well as dynamical mean-field theory of correlated lattice models force us to consider sharp features in the hybridization function near the Fermi energy. Divergencies of this kind can play a relevant role in twisted bilayer graphene, for which local-moment formation and isospin entropy at finite temperature are currently under the spotlight. We clarify how a low-frequency singularity impacts the screening mechanisms by means of a toy model with a tunable $\delta$-peak in the hybridization function, superimposed to a regular part. Our analysis unveils an unexpectedly big impact on the local-moment physics already for a parametrically small weight of the flat band in the bath.

cond-mat.str-el↗

arXiv2025

Stabilization of Fermi-liquid behavior by interactions in disordered metals

We study the interplay of electron-electron and electron-disorder scattering in correlated Fermi liquids by the disordered Hubbard model using dynamical mean-field theory with an IPT-CPA solver. We find significant violations of Matthiessen's rule (additivity of scattering mechanisms) which we explain in terms of the screening of the disorder potential by interactions, leading to a protection of the electron-electron inelastic scattering rate against disorder. We also show that large disorder can lead to a surprising enhancement of the electron-electron scattering that contrasts with the competition seen in the elastic channel. Our results compare positively with available resistivity data in the disordered Fermi liquid phase of the correlated organic metals $κ$-(ET)$_{2}$X, and rationalize the strong sample dependence of the $T^2$ coefficients observed in the resistivity of correlated perovskite oxides such as SrVO$_3$.

cond-mat.str-el↗

arXiv2023

Interacting nodal semimetals with non-linear bands

We investigate the quasi-particle and transport properties of a model describing interacting Dirac and Weyl semimetals in the presence of local Hubbard repulsion $U$, where we explicitly include a deviation from the linearity of the energy-momentum dispersion through an intermediate-energy scale $Λ$. Our focus lies on the correlated phase of the semimetal. At the nodal point, the renormalization of spectral weight at a fixed temperature $T$ exhibits a weak dependence on $Λ$ but is sensitive to the proximity to the Mott transition. Conversely, the scattering rate of quasi-particles and the resistivity display high-temperature exponents that crucially rely on $Λ$, leading to a crossover towards a conventional Fermi-liquid behaviour at finite T. Finally, by employing the Nernst-Einstein relation for conductivity, we identify a corresponding density crossover as a function of the chemical potential.

cond-mat.str-el↗