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arXiv · 2410.15422

Kondo Compensation in a Pseudogap Phase: a Renormalization Group Study

Csanád Hajdú·Cătălin Paşcu Moca·Balázs Dóra·Ireneusz Weymann·Gergely Zaránd
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Abstract

We investigate the critical behavior of the Kondo compensation in the presence of a power-law pseudogap in the density of states, $\varrho(\omega)\sim |\omega|^\epsilon$. For $\epsilon<1$, this model exhibits a quantum phase transition from a partially screened doublet ground state to a fully screened many-body singlet ground state with increasing Kondo coupling, $j$. At the critical point, $j_c$, the Kondo compensation is found to scale as $\kappa(j<j_c) = 1- g(j)$ with the local $g$-factor vanishing as $g \sim |j-j_c|^\beta$. We combine perturbative drone fermion method with non-perturbative NRG computations to determine the critical exponent $\beta (\epsilon)$, which exhibits a non-monotonous behavior as a function of $\epsilon$. Our results confirm that the Kondo cloud builds up continuously in the presence of a weak pseudogap as one approaches the phase transition.

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Csanád Hajdú, Cătălin Paşcu Moca, Balázs Dóra, Ireneusz Weymann, Gergely Zaránd. 2024-10-20. Kondo Compensation in a Pseudogap Phase: a Renormalization Group Study. https://doi.org/10.1103/physrevb.111.155125

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