Numerical Renormalization Group Study of Quadrupole Kondo Effect with the Crystal-field Excited State

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Main Authors: Kaneko, Yuki, Tsunetsugu, Hirokazu
Format: Preprint
Published: 2023
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author Kaneko, Yuki
Tsunetsugu, Hirokazu
author_facet Kaneko, Yuki
Tsunetsugu, Hirokazu
contents We have studied the quadrupolar Kondo effect for an impurity in cubic environment with taking account of a singlet excited state $Γ_1$, which models a $\mathrm{Pr}^{3+}$ ion with a non-Kramers double ground state $Γ_3$. We have used the numerical renormalization group approach and determined the phase diagram with varying quadrupole Kondo coupling $J$ and $Γ_1$ excitation energy $Δ$. Two phases are found and identified as local Fermi liquid and non-Fermi liquid. This non-Fermi liquid phase is characteristic to the two-channel Kondo impurity, and a similar phase diagram has been also found in other extended quadrupole models. We have analyzed in detail the $J$-dependence of the Kondo temperature $T_K$ near the phase boundary $J_c (Δ) $ and found a nice scaling behavior with an stretched exponential form $T_K \sim δJ^α \exp (-\mathrm{const.}/\sqrt{δJ})$ where $δJ \equiv J - J_c (Δ)$. This differs from the standard scaling form and indicates that one needs to consider renormalization of multiple coupling constants.
format Preprint
id arxiv_https___arxiv_org_abs_2312_15936
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Numerical Renormalization Group Study of Quadrupole Kondo Effect with the Crystal-field Excited State
Kaneko, Yuki
Tsunetsugu, Hirokazu
Strongly Correlated Electrons
We have studied the quadrupolar Kondo effect for an impurity in cubic environment with taking account of a singlet excited state $Γ_1$, which models a $\mathrm{Pr}^{3+}$ ion with a non-Kramers double ground state $Γ_3$. We have used the numerical renormalization group approach and determined the phase diagram with varying quadrupole Kondo coupling $J$ and $Γ_1$ excitation energy $Δ$. Two phases are found and identified as local Fermi liquid and non-Fermi liquid. This non-Fermi liquid phase is characteristic to the two-channel Kondo impurity, and a similar phase diagram has been also found in other extended quadrupole models. We have analyzed in detail the $J$-dependence of the Kondo temperature $T_K$ near the phase boundary $J_c (Δ) $ and found a nice scaling behavior with an stretched exponential form $T_K \sim δJ^α \exp (-\mathrm{const.}/\sqrt{δJ})$ where $δJ \equiv J - J_c (Δ)$. This differs from the standard scaling form and indicates that one needs to consider renormalization of multiple coupling constants.
title Numerical Renormalization Group Study of Quadrupole Kondo Effect with the Crystal-field Excited State
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2312.15936